[fc] Log out correct port ID after a successful LOGO request

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/fcels.c

 				     size_t len __unused ) {
 
 	/* Log out individual peer or whole port as applicable */
-	fc_els_logo_logout ( els, &els->port_id );
+	fc_els_logo_logout ( els, &els->peer_port_id );
 
 	return 0;
 }