hikey960: gralloc960: Add support for building w/  drm_hwcomposer

If we're building with drm_hwcomposer, we need to set the
following gralloc960 flags:

 ION_DMA_HEAP=1
 DISABLE_FRAMEBUFFER_HAL=1

Change-Id: I832993b0ade105c3f72c81a28de2b8c336d283e2
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/gralloc960/Android.hikey960.mk b/gralloc960/Android.hikey960.mk
index 5a1a958..8b0b1be 100644
--- a/gralloc960/Android.hikey960.mk
+++ b/gralloc960/Android.hikey960.mk
@@ -51,3 +51,9 @@
 GRALLOC_DISP_H=0
 # Vsync backend(not used)
 GRALLOC_VSYNC_BACKEND=default
+
+ifeq ($(HIKEY_USE_DRM_HWCOMPOSER), true)
+ GRALLOC_USE_ION_DMA_HEAP=1
+ GRALLOC_DISABLE_FRAMEBUFFER_HAL=1
+endif
+