Also change the device probing scheme to use something a bit more rational.
A current side-effect is that nubus cards are double-mapped. I expect
to fix that shortly.
Also change splclock() to block everything but serial hardware interrupts.
a condition that occurs with some slow SCSI devices when they disconnect
(e.g. the AppleCD 600), generating spurious selection interrupts.
- Reorganize the debugging code slightly.
scottr