Fis the value of *optlen when calling getsockopt() for

SCTP_REMOTE_UDP_ENCAPS_PORT.
This issue was reported by Andrew Galante.
MFC after: 3 days

sys/netinet/sctp_usrreq.c

@@ -3281,7 +3281,7 @@ flags_out:
 				}
 			}
 			if (error == 0) {
-				*optsize = sizeof(struct sctp_paddrparams);
+				*optsize = sizeof(struct sctp_udpencaps);
 			}
 			break;
 		}