[pattgen,doc] Pattgen HWIP Specification

This PR contains the specification and CSR definitions for the Pattgen HWIP, which
generates simple time-dependent signals on one or two channels.

Co-authored-by: Philipp Wagner <mail@philipp-wagner.com>
Co-authored-by: @tunghoang290780 <hoang.tung@wdc.com>

Signed-off-by: Martin Lueker-Boden <martin.lueker-boden@wdc.com>
diff --git a/util/build_docs.py b/util/build_docs.py
index 4735b4b..123dc1b 100755
--- a/util/build_docs.py
+++ b/util/build_docs.py
@@ -69,6 +69,7 @@
         "hw/ip/otbn/data/otbn.hjson",
         "hw/ip/otp_ctrl/data/otp_ctrl.hjson",
         "hw/ip/padctrl/data/padctrl.hjson",
+        "hw/ip/pattgen/data/pattgen.hjson",
         "hw/top_earlgrey/ip/pinmux/data/autogen/pinmux.hjson",
         "hw/top_earlgrey/ip/pwrmgr/data/autogen/pwrmgr.hjson",
         "hw/top_earlgrey/ip/rstmgr/data/autogen/rstmgr.hjson",
@@ -97,6 +98,7 @@
         "hw/ip/i2c/data/i2c_testplan.hjson",
         "hw/ip/keymgr/data/keymgr_testplan.hjson",
         "hw/ip/padctrl/data/padctrl_fpv_testplan.hjson",
+        "hw/ip/pattgen/data/pattgen_testplan.hjson",
         "hw/ip/pinmux/data/pinmux_fpv_testplan.hjson",
         "hw/ip/rv_plic/data/rv_plic_fpv_testplan.hjson",
         "hw/ip/rv_timer/data/rv_timer_testplan.hjson",