staging/lustre/ldlm: Correct itree_overlap_cb return type

As per interval_search() prototype, the callback should return
enum, not int.
This fixes correspondign sparse warning.
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ldlm/ldlm_lock.c

@@ -1148,7 +1148,7 @@ static int lock_matches(struct ldlm_lock *lock, struct lock_match_data *data)
 	return INTERVAL_ITER_STOP;
 }
 
-static unsigned int itree_overlap_cb(struct interval_node *in, void *args)
+static enum interval_iter itree_overlap_cb(struct interval_node *in, void *args)
 {
 	struct ldlm_interval *node = to_ldlm_interval(in);
 	struct lock_match_data *data = args;