Generalize the workaround for the Hitachi HT-4840-11. The Contec

Generalize the workaround for the Hitachi HT-4840-11.  The Contec
C-NET(PC) has a cfe at location 1 that has both an odd irq mask (it
matches pc98 machines, so maybe it was a flag for pc98 operation) as
well as a memory map.  Since this driver doesn't know how to cope, we
start with cfe2, which is purely an I/O space mapped and that seems to
make it work.  I say 'seems' here, because the card I have doesn't
seem to have the right dongle for full testing...