naming conflicts between bus attachments on ports that can have
multiple instances of the LANCE.
Break up ISA LANCE driver into ISA and PCI front-ends.
Changed struct ifnet to have a pointer to the softc of the underlying
device and a printable "external name" (name + unit number), thus eliminating
if_name and if_unit. Updated interface to (*if_watchdog)() and (*if_start)()
to take a struct ifnet *, rather than a unit number.