enable EGL_IMG_context_priority for the omap4 platform

Bug: 5311015
Change-Id: Icaad3d1c963d382ac0a4b9121fe20d3408846c2b
diff --git a/services/surfaceflinger/Android.mk b/services/surfaceflinger/Android.mk
index 51eb0a3..dab0705 100644
--- a/services/surfaceflinger/Android.mk
+++ b/services/surfaceflinger/Android.mk
@@ -22,6 +22,9 @@
 ifeq ($(TARGET_BOARD_PLATFORM), omap3)
 	LOCAL_CFLAGS += -DNO_RGBX_8888
 endif
+ifeq ($(TARGET_BOARD_PLATFORM), omap4)
+	LOCAL_CFLAGS += -DHAS_CONTEXT_PRIORITY
+endif
 ifeq ($(TARGET_BOARD_PLATFORM), s5pc110)
 	LOCAL_CFLAGS += -DHAS_CONTEXT_PRIORITY -DNEVER_DEFAULT_TO_ASYNC_MODE
 endif