sctp: use list_move_tail instead of list_del/list_add_tail

Using list_move_tail() instead of list_del() + list_add_tail().

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/outqueue.c

@@ -591,8 +591,7 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
 		 * next chunk.
 		 */
 		if (chunk->tsn_gap_acked) {
-			list_del(&chunk->transmitted_list);
-			list_add_tail(&chunk->transmitted_list,
+			list_move_tail(&chunk->transmitted_list,
 				       &transport->transmitted);
 			continue;
 		}
@@ -657,8 +656,7 @@ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
 			/* The append was successful, so add this chunk to
 			 * the transmitted list.
 			 */
-			list_del(&chunk->transmitted_list);
-			list_add_tail(&chunk->transmitted_list,
+			list_move_tail(&chunk->transmitted_list,
 				       &transport->transmitted);
 
 			/* Mark the chunk as ineligible for fast retransmit