ether_input/rss: Pass packet info to ether_input_chain.

ether_input/rss: Pass packet info to ether_input_chain.

- Pass packet info to ether_input_chain(), if netisr_find_pktinfo_port()
  could locate the msgport, then short circuit the rest of the ether_input
  code and dispatch the ethernet packet directly.
- Revoke the pi_hash field in pktinfo and extend the pktinfo_portfn_t to
  accpet an mbuf parameter, so that pktinfo_portfn_t could change the mbuf
  hash value.  e.g. pktinfo_portfn_cpu0() will always set m_pkthdr.hash
  to 0.
- Adjust ether_input_chain() callers accordingly.