msm: camera_v2: fix unbalanced mutex

Change-Id: Ie636f8b0a5129d35de7a6a6870d370f6f5374f94
Signed-off-by: Jongrak Kwon <jongrak.kwon@lge.com>

drivers/media/platform/msm/camera_v2/msm.c

@@ -407,8 +407,10 @@ void msm_delete_command_ack_q(unsigned int session_id, unsigned int stream_id)
 	cmd_ack = msm_queue_find(&session->command_ack_q,
 		struct msm_command_ack,	list, __msm_queue_find_command_ack_q,
 		&stream_id);
-	if (!cmd_ack)
+	if (!cmd_ack) {
+		mutex_unlock(&session->lock);
 		return;
+	}
 
 	msm_queue_drain(&cmd_ack->command_q, struct msm_command, list);