lagg_port_ioctl fallback forwards ioctl to driver but always returns EINVAL discarding result

Summary

lagg_port_ioctl fallback(:896-902) calls result=(*lp->lp_ioctl)(ifp,cmd,data,cr) into local var then unconditionally return(EINVAL). Driver side effects applied but caller told EINVAL regardless. Dead-store of result. Confused-deputy for ifconfig tooling. Fix: return result.