sctp: use list_* in sctp_list_dequeue

Use list_* helpers in sctp_list_dequeue, more readable.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/sctp.h

@@ -386,11 +386,9 @@ static inline struct list_head *sctp_list_dequeue(struct list_head *list)
 {
 	struct list_head *result = NULL;
 
-	if (list->next != list) {
+	if (!list_empty(list)) {
 		result = list->next;
-		list->next = result->next;
-		list->next->prev = list;
-		INIT_LIST_HEAD(result);
+		list_del_init(result);
 	}
 	return result;
 }