Instead, print a diagnostic and return. (Some drivers do this already.)
Also, normalize the diagnostic message, and fix some places where the
printfs were getting ugly.
Some of the stuff (e.g., rarpd, bootpd, dhcpd etc., libsa) still will
only support Ethernet. Tcpdump itself should be ok, but libpcap needs
lot of work.
For the detailed change history, look at the commit log entries for
the is-newarp branch.
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.
