sctp: Remove rt->rt_src usage in sctp_v4_get_saddr()

Flow key is available, so fetch it from there.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/protocol.c

@@ -566,7 +566,7 @@ static void sctp_v4_get_saddr(struct sctp_sock *sk,
 
 	if (rt) {
 		saddr->v4.sin_family = AF_INET;
-		saddr->v4.sin_addr.s_addr = rt->rt_src;
+		saddr->v4.sin_addr.s_addr = fl->u.ip4.saddr;
 	}
 }