Camera2: Compile with warnings, fix warnings

Change-Id: I557350abb32b0480f5da7dcecadfbe9edbe53361
diff --git a/services/camera/libcameraservice/Android.mk b/services/camera/libcameraservice/Android.mk
index eff47c8..801afe9 100644
--- a/services/camera/libcameraservice/Android.mk
+++ b/services/camera/libcameraservice/Android.mk
@@ -40,6 +40,9 @@
     system/media/camera/include \
     external/jpeg
 
+
+LOCAL_CFLAGS += -Wall -Wextra
+
 LOCAL_MODULE:= libcameraservice
 
 include $(BUILD_SHARED_LIBRARY)