msm: camera: Use wall clock for event timestamp

Certain camera features need realtime clock for
calculation. This change add support to store realtime
clock and send the timestamp for userspace notification.

Change-Id: Ifa565a0d888e34a47c5e6e9e0a849c767e0e7e09
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>
diff --git a/include/media/msmb_isp.h b/include/media/msmb_isp.h
index c9d3f15..26ad185 100644
--- a/include/media/msmb_isp.h
+++ b/include/media/msmb_isp.h
@@ -324,7 +324,7 @@
 };
 
 struct msm_isp_event_data {
-	struct timeval timestamp;
+	struct timeval timestamp; /*Wall clock*/
 	/* if pix is a src frame_id is from camif */
 	uint32_t frame_id;
 	union {