Allow implicit-fallthrough warnings locally.

It will be a global error by default.

Test: make checkbuild
Bug: 112564944
Change-Id: I3e914835fcb4ee97662ab51136f143e665d0ba01
Exempt-From-Owner-Approval: do not block on new warnings
diff --git a/broadcastradio/common/utils2x/Android.bp b/broadcastradio/common/utils2x/Android.bp
index aab94f2..df2cefe 100644
--- a/broadcastradio/common/utils2x/Android.bp
+++ b/broadcastradio/common/utils2x/Android.bp
@@ -22,6 +22,7 @@
         "-Wall",
         "-Wextra",
         "-Werror",
+        "-Wno-error=implicit-fallthrough",
     ],
     cppflags: [
         "-std=c++1z",