[dif/uart] Update DIF milestone and checklist

This updates the DIF checklist for the UART to reflect the current state
of the software.

Signed-off-by: Timothy Trippel <ttrippel@google.com>
diff --git a/hw/ip/uart/data/uart.prj.hjson b/hw/ip/uart/data/uart.prj.hjson
index 0f55670..5d14ce3 100644
--- a/hw/ip/uart/data/uart.prj.hjson
+++ b/hw/ip/uart/data/uart.prj.hjson
@@ -22,7 +22,7 @@
         life_stage:         "L1",
         design_stage:       "D2S",
         verification_stage: "V2",
-        dif_stage:          "S1",
+        dif_stage:          "S2",
         notes:              "Rolled back to D2 as the register module is updated"
       }
     ]
diff --git a/sw/device/lib/dif/dif_uart.md b/sw/device/lib/dif/dif_uart.md
index bf5f19c..e095489 100644
--- a/sw/device/lib/dif/dif_uart.md
+++ b/sw/device/lib/dif/dif_uart.md
@@ -5,63 +5,48 @@
 This checklist is for [Development Stage]({{< relref "/doc/project/development_stages.md" >}}) transitions for the [UART DIF]({{< relref "hw/ip/uart/doc" >}}).
 All checklist items refer to the content in the [Checklist]({{< relref "/doc/project/checklist.md" >}}).
 
-## DIF Checklist
+<h2>DIF Checklist</h2>
 
-### S1
+<h3>S1</h3>
 
 Type           | Item                 | Resolution  | Note/Collaterals
 ---------------|----------------------|-------------|------------------
 Implementation | [DIF_EXISTS][]       | Done        |
 Implementation | [DIF_USED_IN_TREE][] | Done        |
-Tests          | [DIF_TEST_UNIT][]    | Done        |
 Tests          | [DIF_TEST_SMOKE][]   | Done        |
 
 [DIF_EXISTS]:       {{< relref "/doc/project/checklist.md#dif_exists" >}}
 [DIF_USED_IN_TREE]: {{< relref "/doc/project/checklist.md#dif_used_in_tree" >}}
-[DIF_TEST_UNIT]:    {{< relref "/doc/project/checklist.md#dif_test_unit" >}}
 [DIF_TEST_SMOKE]:   {{< relref "/doc/project/checklist.md#dif_test_smoke" >}}
 
-### S2
+<h3>S2</h3>
 
 Type           | Item                        | Resolution  | Note/Collaterals
 ---------------|-----------------------------|-------------|------------------
-Implementation | [DIF_FEATURES][]            | Not Started |
-Coordination   | [DIF_HW_USAGE_REVIEWED][]   | Done        |
-Coordination   | [DIF_HW_FEATURE_COMPLETE][] | Not Started | [HW Dashboard]({{< relref "hw" >}})
-Implementation | [DIF_HW_PARAMS][]           | Not Started |
-Documentation  | [DIF_DOC_HW][]              | Not Started |
-Documentation  | [DIF_DOC_API][]             | Not Started |
-Code Quality   | [DIF_CODE_STYLE][]          | Not Started |
-Coordination   | [DIF_DV_TESTS][]            | Not Started |
-Implementation | [DIF_USED_TOCK][]           | Not Started |
-Review         | HW IP Usage Reviewer(s)     | Not Started | @eunchan
+Coordination   | [DIF_HW_FEATURE_COMPLETE][] | Done        | [HW Dashboard]({{< relref "hw" >}})
+Implementation | [DIF_FEATURES][]            | Done        |
+Coordination   | [DIF_DV_TESTS][]            | Done        |
 
-[DIF_FEATURES]:            {{< relref "/doc/project/checklist.md#dif_features" >}}
-[DIF_HW_USAGE_REVIEWED]:   {{< relref "/doc/project/checklist.md#dif_hw_usage_reviewed" >}}
 [DIF_HW_FEATURE_COMPLETE]: {{< relref "/doc/project/checklist.md#dif_hw_feature_complete" >}}
-[DIF_HW_PARAMS]:           {{< relref "/doc/project/checklist.md#dif_hw_params" >}}
-[DIF_DOC_HW]:              {{< relref "/doc/project/checklist.md#dif_doc_hw" >}}
-[DIF_DOC_API]:             {{< relref "/doc/project/checklist.md#dif_doc_api" >}}
-[DIF_CODE_STYLE]:          {{< relref "/doc/project/checklist.md#dif_code_style" >}}
+[DIF_FEATURES]:            {{< relref "/doc/project/checklist.md#dif_features" >}}
 [DIF_DV_TESTS]:            {{< relref "/doc/project/checklist.md#dif_dv_tests" >}}
-[DIF_USED_TOCK]:           {{< relref "/doc/project/checklist.md#dif_used_tock" >}}
 
-### S3
+<h3>S3</h3>
 
 Type           | Item                             | Resolution  | Note/Collaterals
 ---------------|----------------------------------|-------------|------------------
 Coordination   | [DIF_HW_DESIGN_COMPLETE][]       | Not Started |
 Coordination   | [DIF_HW_VERIFICATION_COMPLETE][] | Not Started |
-Review         | [DIF_REVIEW_C_STABLE][]          | Not Started |
-Tests          | [DIF_TEST_UNIT_COMPLETE][]       | Not Started |
+Documentation  | [DIF_DOC_HW][]                   | Not Started |
+Code Quality   | [DIF_CODE_STYLE][]               | Not Started |
+Tests          | [DIF_TEST_UNIT][]                | Done        |
 Review         | [DIF_TODO_COMPLETE][]            | Not Started |
-Review         | [DIF_REVIEW_TOCK_STABLE][]       | Not Started |
 Review         | Reviewer(s)                      | Not Started |
 Review         | Signoff date                     | Not Started |
 
 [DIF_HW_DESIGN_COMPLETE]:       {{< relref "/doc/project/checklist.md#dif_hw_design_complete" >}}
 [DIF_HW_VERIFICATION_COMPLETE]: {{< relref "/doc/project/checklist.md#dif_hw_verification_complete" >}}
-[DIF_REVIEW_C_STABLE]:          {{< relref "/doc/project/checklist.md#dif_review_c_stable" >}}
-[DIF_TEST_UNIT_COMPLETE]:       {{< relref "/doc/project/checklist.md#dif_test_unit_complete" >}}
+[DIF_DOC_HW]:                   {{< relref "/doc/project/checklist.md#dif_doc_hw" >}}
+[DIF_CODE_STYLE]:               {{< relref "/doc/project/checklist.md#dif_code_style" >}}
+[DIF_TEST_UNIT]:                {{< relref "/doc/project/checklist.md#dif_test_unit" >}}
 [DIF_TODO_COMPLETE]:            {{< relref "/doc/project/checklist.md#dif_todo_complete" >}}
-[DIF_REVIEW_TOCK_STABLE]:       {{< relref "/doc/project/checklist.md#dif_review_tock_stable" >}}