Use -Werror in hardware/qcom/audio

* Suppress existing warnings.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I389b943471ccdcfc9b7db4411fa3973d77303a27
diff --git a/visualizer/Android.mk b/visualizer/Android.mk
index e318214..4b73704 100644
--- a/visualizer/Android.mk
+++ b/visualizer/Android.mk
@@ -21,6 +21,11 @@
 
 LOCAL_CFLAGS+= -O2 -fvisibility=hidden
 
+LOCAL_CFLAGS+= \
+    -Wall \
+    -Werror \
+    -Wno-unused-variable \
+
 LOCAL_SHARED_LIBRARIES := \
 	libcutils \
 	liblog \