ANDROID: Clang LTO: Comment on symbol visibility workaround

This commit leaves a TODO in the code so we can more easily keep track
of the workaround.

Bug: 182572011
Fixes: be409db65233 ("ANDROID: Clang LTO: Only set -fvisibility=hidden for x86")
Signed-off-by: Giuliano Procida <gprocida@google.com>
Change-Id: I0277a8c0704e5caf8885884ec4e3642ebe03667f
diff --git a/Makefile b/Makefile
index 5e5a887..6f46b59 100644
--- a/Makefile
+++ b/Makefile
@@ -908,7 +908,7 @@
 endif
 
 ifeq ($(SRCARCH),x86)
-# Workaround for compiler / linker bug
+# TODO(b/182572011): Revert workaround for compiler / linker bug.
 CC_FLAGS_LTO	+= -fvisibility=hidden
 else
 CC_FLAGS_LTO	+= -fvisibility=default