Update the list of struct ifnet fields.
- Document if_vnet, if_home_vnet, if_carp, if_vlantrunk, if_multiaddrs,
if_amcount, if_addr, if_llsoftc stub, if_broadcastaddr, if_bridge,
if_label, if_afdata, if_afdata_initialized, if_afdata_lock, if_linktask,
if_addr_mtx (now if_addr_lock), if_clones, if_groups, if_pf_kif, if_lagg,
if_alloctype
- G/c now defunct and/or commented out in the manual page if_ipending,
if_poll_slowq, if_done, if_poll_recv, if_poll_xmit, if_poll_slowinput,
if_poll_intren
- Update if_snd type changed with ALTQ integration.
MFC after: 1 week
8a9b1b14f6