Set -Oz for all cc targets.

Bug: 71844955
Change-Id: Icb544bd8892aa6d1a4a7de577373798256870a58
diff --git a/tools/gen_android_bp b/tools/gen_android_bp
index fa81052..5f563ac 100755
--- a/tools/gen_android_bp
+++ b/tools/gen_android_bp
@@ -505,6 +505,7 @@
         '-Wno-sign-promo',
         '-Wno-unused-parameter',
         '-fvisibility=hidden',
+        '-Oz',
     ]
 
     blueprint.add_module(defaults)