display: Enable clang for all display modules

Change-Id: I71e3fa3f7d44253b8e01d1eafe086b1898d65a8e
diff --git a/hdmi_cec/Android.mk b/hdmi_cec/Android.mk
index ed06da1..3b794e3 100644
--- a/hdmi_cec/Android.mk
+++ b/hdmi_cec/Android.mk
@@ -8,7 +8,8 @@
 LOCAL_C_INCLUDES              := $(common_includes)
 LOCAL_SHARED_LIBRARIES        := $(common_libs) libqservice libbinder libqdutils
 
-LOCAL_CFLAGS                  := $(common_flags) -DLOG_TAG=\"qdhdmi_cec\"
+LOCAL_CFLAGS                  := $(common_flags) -DLOG_TAG=\"qdhdmi_cec\" -Wno-sign-conversion
+LOCAL_CLANG                   := true
 LOCAL_ADDITIONAL_DEPENDENCIES := $(common_deps)
 LOCAL_SRC_FILES               := qhdmi_cec.cpp \
                                  QHDMIClient.cpp