When performing a restart (CSR0 STOP, STRT), the behavior regarding
the NIC's current RX/TX descriptor ring counters varies between cards:
older LANCE cards do not reset the counters; newer PCnet cards do
reset them; VirtualBox's emulation is once again broken in that it
claims to emulate newer cards but implements the older behavior.
Changing the card's receive mode requires such a restart, and now that
the system can actually change receive modes dynamically as part of
normal network operation, this results in the lance driver breaking
all the time on at least VirtualBox.
Instead of trying to figure out exactly what is going on with the
counters during a restart, we now simply perform a full-blown
reinitialization every time the NIC is restarted. That leaves no
ambiguity regarding the counters, and appears to be what drivers on
other OSes do as well. As a bonus, this approach actually saves code.