Allow to force 16bpp when 32bpp has problems

Bug: 4197654

Change-Id: Icf1e8793d6a4d2e070a8f232efd4136d79339496
diff --git a/modules/gralloc/Android.mk b/modules/gralloc/Android.mk
index ac09e5a..cbfd82b 100644
--- a/modules/gralloc/Android.mk
+++ b/modules/gralloc/Android.mk
@@ -32,5 +32,8 @@
 ifeq ($(BOARD_NO_PAGE_FLIPPING),true)
 LOCAL_CFLAGS += -DNO_PAGE_FLIPPING
 endif
+ifeq ($(BOARD_NO_32BPP),true)
+LOCAL_CFLAGS += -DNO_32BPP
+endif
 
 include $(BUILD_SHARED_LIBRARY)