Use -Werror in hardware/interfaces/automotive/vehicle/2.0

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I4de457fc522b490d0142b1f21552b993553a5982
Merged-In: I851c9b2ff956b0f6d9d7a6076d495aad9038a66a
diff --git a/automotive/vehicle/2.0/default/Android.mk b/automotive/vehicle/2.0/default/Android.mk
index ebc565d..141cda6 100644
--- a/automotive/vehicle/2.0/default/Android.mk
+++ b/automotive/vehicle/2.0/default/Android.mk
@@ -91,6 +91,8 @@
 LOCAL_EXPORT_C_INCLUDE_DIRS := \
     $(generated_sources_dir)/proto/$(LOCAL_PATH)/impl/vhal_v2_0/proto
 
+LOCAL_CFLAGS += -Wall -Wextra -Werror
+
 include $(BUILD_STATIC_LIBRARY)