msm: display: buf sync enhancement

Support waiting for acquire fences in the buffer sync ioctl.

Signed-off-by: Ken Zhang <kenz@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>
diff --git a/include/linux/msm_mdp.h b/include/linux/msm_mdp.h
index 01737da..11861e1 100644
--- a/include/linux/msm_mdp.h
+++ b/include/linux/msm_mdp.h
@@ -490,6 +490,7 @@
 };
 
 #define MDP_MAX_FENCE_FD	10
+#define MDP_BUF_SYNC_FLAG_WAIT	1
 
 struct mdp_buf_sync {
 	uint32_t flags;