Changes to support uninorth bridge (probably a bit of a hack for now).

Changes to support uninorth bridge (probably a bit of a hack for now).
cleaned up the previous support for the macobio that was there previously.

Now registers real interupt handler devices instead of the pseudo configed
ones before.

The G4 systems are not yet working, the onboard ide configures properly
and interrupts seem to work, but the system hangs before mounting
the root drive (even ramdisks). Maybe someone will point out something
bogus in the code, so it is being checked in.