Provide pr_ctloutput method for AF_LOCAL/SOCK_SEQPACKET sockets.

This makes setsockopt() on them working.

Reported by:	Yuri <yuri rawbw.com>
Approved by:	re (kib)

sys/kern/uipc_usrreq.c

@@ -325,6 +325,7 @@ static struct protosw localsw[] = {
 	 */
 	.pr_flags =		PR_ADDR|PR_ATOMIC|PR_CONNREQUIRED|PR_WANTRCVD|
 				    PR_RIGHTS,
+	.pr_ctloutput =		&uipc_ctloutput,
 	.pr_usrreqs =		&uipc_usrreqs_seqpacket,
 },
 };