sctp: remove redundant assignment when call sctp_get_port_local

There are more parentheses in if clause when call sctp_get_port_local
in sctp_do_bind, and redundant assignment to 'ret'. This patch is to
do cleanup.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -399,9 +399,8 @@ static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
 	 * detection.
 	 */
 	addr->v4.sin_port = htons(snum);
-	if ((ret = sctp_get_port_local(sk, addr))) {
+	if (sctp_get_port_local(sk, addr))
 		return -EADDRINUSE;
-	}
 
 	/* Refresh ephemeral port.  */
 	if (!bp->port)