configuration of devices logically attached to the ISA bus:
* Change the isa_attach_args to have arrays of io, mem, irq, drq
resources.
* Add a "pnpnames" and a linked list of "pnpcompatnames" to the
isa_attach_args. If either of these members are non-NULL,
direct configuration of the bus is being performed. Add an
ISA_DIRECT_CONFIG() macro to test for this.
* Drivers are not allowed to modify the isa_attach_args unless
direct configuration is not being performed and the probe fucntion
is returning success.
* Adapt device drivers -- currently, all driver probe routines return
"no match" if ISA_DIRECT_CONFIG() evaluates to true.
but the registers actually begin at 0x3f2, and this is what PNPBIOS reports
for the floppy controller resources. Adjust the register offsets and the
mapping of them for the ISA front-end to compensate, so that the PNPBIOS
attachment of the floppy controller actually works.