[bazel] Deprecate the :freestanding target.

Signed-off-by: Miguel Young de la Sota <mcyoung@google.com>
diff --git a/sw/device/lib/base/freestanding/BUILD b/sw/device/lib/base/freestanding/BUILD
index ab4321a..eee51ed 100644
--- a/sw/device/lib/base/freestanding/BUILD
+++ b/sw/device/lib/base/freestanding/BUILD
@@ -18,4 +18,7 @@
         "stdint.h",
         "stdnoreturn.h",
     ],
+    deprecation =
+        "Do not depend on this target; instead, include its headers via " +
+        "system header includes like #include <stdint.h>",
 )
diff --git a/sw/device/lib/runtime/BUILD b/sw/device/lib/runtime/BUILD
index 921abe6..192f391 100644
--- a/sw/device/lib/runtime/BUILD
+++ b/sw/device/lib/runtime/BUILD
@@ -11,9 +11,6 @@
     srcs = ["epmp.c"],
     hdrs = ["epmp.h"],
     target_compatible_with = [OPENTITAN_CPU],
-    deps = [
-        "//sw/device/lib/base/freestanding",
-    ],
 )
 
 cc_library(
@@ -26,7 +23,6 @@
         "//sw/device/lib/arch:device",
         "//sw/device/lib/base:math",
         "//sw/device/lib/base:stdasm",
-        "//sw/device/lib/base/freestanding",
     ],
 )
 
@@ -53,7 +49,6 @@
         "//sw/device/lib/base:macros",
         "//sw/device/lib/base:memory",
         "//sw/device/lib/base:mmio",
-        "//sw/device/lib/base/freestanding",
         "//sw/device/lib/runtime:print",
     ],
 )
@@ -77,7 +72,6 @@
         "//sw/device/lib/base:bitfield",
         "//sw/device/lib/base:csr",
         "//sw/device/lib/base:macros",
-        "//sw/device/lib/base/freestanding",
     ],
 )