SF: Remove "-fvisibility=hidden" flag from sf build

This flag along with -fwhole-program-vtables may result in ODR violations. See
bug for more details.

Fixes: 217612145
Test: ag/16761579 no longer repros
Change-Id: Ic85d934c6e1a3706382a80cf09048b86543208b6
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index af0f524..d9958f3 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -118,9 +118,6 @@
 cc_defaults {
     name: "libsurfaceflinger_production_defaults",
     defaults: ["libsurfaceflinger_defaults"],
-    cflags: [
-        "-fvisibility=hidden",
-    ],
     lto: {
         thin: true,
     },