gralloc1: Map secure display flag.

Change-Id: I885f0a378aa0a4034b83e4fa9533878c03fc2335
diff --git a/libgralloc1/gralloc_priv.h b/libgralloc1/gralloc_priv.h
index 87604c6..2abdd84 100644
--- a/libgralloc1/gralloc_priv.h
+++ b/libgralloc1/gralloc_priv.h
@@ -78,6 +78,7 @@
 #define GRALLOC_USAGE_PRIVATE_IOMMU_HEAP GRALLOC1_PRODUCER_USAGE_PRIVATE_IOMMU_HEAP
 #define GRALLOC_USAGE_PRIVATE_WFD GRALLOC1_CONSUMER_USAGE_PRIVATE_WFD
 #define GRALLOC_USAGE_PRIVATE_CAMERA_HEAP GRALLOC1_PRODUCER_USAGE_PRIVATE_CAMERA_HEAP
+#define GRALLOC_USAGE_PRIVATE_SECURE_DISPLAY GRALLOC1_CONSUMER_USAGE_PRIVATE_SECURE_DISPLAY
 #define GRALLOC_USAGE_PRIVATE_MM_HEAP 0x0