For the ISA probe, implement a way to keep track of which ISA busses
have been through an ep_isa probe; the static variable that was used
before didn't scale.
bus-independent core driver. Tested on all three bus types, including
an isa 3c509 masquerading as an eisa device (use ep* at eisa? slot ? in
your kernel config file to catch this one).
XXX Driver still needs to be converted to <machine/bus.h>
christos