new simple prio queuer: enqueue


(m)->m_nextpkt = NULL;
if ((ifq)->ifq_q[(m)->m_pkthdr.pf.prio].tail == NULL)
      (ifq)->ifq_q[(m)->m_pkthdr.pf.prio].head = m;
else
      (ifq)->ifq_q[(m)->m_pkthdr.pf.prio].tail->
         m_nextpkt = m;
(ifq)->ifq_q[(m)->m_pkthdr.pf.prio].tail = m;
(ifq)->ifq_len++;