ipc/mqueue: add missing sparse annotation

Link: http://lkml.kernel.org/r/20170128235704.45302-1-luc.vanoostenryck@gmail.com
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/mqueue.c

@@ -558,6 +558,7 @@ static void wq_add(struct mqueue_inode_info *info, int sr,
  */
 static int wq_sleep(struct mqueue_inode_info *info, int sr,
 		    ktime_t *timeout, struct ext_wait_queue *ewp)
+	__releases(&info->lock)
 {
 	int retval;
 	signed long time;