Only compile libva when IMG graphics is enabled

Change-Id: Ic473cf993b648e06cee3be3b23317bf534d901b2
diff --git a/va/Android.mk b/va/Android.mk
index b10b643..18e8053 100755
--- a/va/Android.mk
+++ b/va/Android.mk
@@ -25,6 +25,8 @@
 
 LOCAL_PATH:= $(call my-dir)
 
+ifeq ($(ENABLE_IMG_GRAPHICS),true)
+
 LIBVA_DRIVERS_PATH = /system/lib
 
 # Version set to Android Jelly Bean
@@ -176,3 +178,5 @@
 LOCAL_MODULE := libva-tpi
 
 include $(BUILD_SHARED_LIBRARY)
+
+endif # $(ENABLE_IMG_GRAPHICS),true)