gralloc: Add metadata type buffer_type

CRs-Fixed: 2730864
Change-Id: I8f96b5dc905f1b8cedc498d3853be27a8f92ae58
diff --git a/gralloc/QtiGrallocMetadata.h b/gralloc/QtiGrallocMetadata.h
index cc134a8..35bf4a0 100644
--- a/gralloc/QtiGrallocMetadata.h
+++ b/gralloc/QtiGrallocMetadata.h
@@ -55,6 +55,7 @@
 // Indicates whether metadata is using default value or has been set
 #define QTI_STANDARD_METADATA_STATUS 10016
 #define QTI_VENDOR_METADATA_STATUS 10017
+#define QTI_BUFFER_TYPE 10018
 
 // Used to indicate to framework that internal definitions are used instead
 #define COMPRESSION_QTI_UBWC 20001