Now that we've sanitzed io_mm.h, revisit support for the 100 Mbit APNE
PCMCIA card variants that didn't find favour with the netdev folks three
years ago.

Add another ISA type for these cards, and switch to that type from the
APNE probe code in response to a module parameter. 

I've addressed review comments received so far, to the best of my ability.

Compile tested only - hopefully someone will be encouraged to give this
a try before I submit the apne.c patch to netdev. 

Cheers,

   Michael