do not touch m after IFQ_ENQUEUE()+if_start().
do not touch m after IFQ_ENQUEUE()+if_start().

ok brad@, mpf@, henning@, reyk@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars