the CDIOC* calls correctly, improve performance by 10x when interrupts work,
and implement the same generic disk framework as other drivers.
Needs some more work.
round: moving the drivers into a machine-independent directory.
Some drivers (e.g. fd.c) not moved because they use other pc features (e.g.
CMOS settings), and none of the non-driver files moved, because they're
still pretty much PC specific. eventually (when other ports with ISA
busses really start using this code), more 'high-level' ISA support will
live here.
* Forget all cached info when opening a new disc.
* If the disc is removed, flush the buffer queue rather than stalling it.
* Set the default label after getting the disc size, and fill in the info
for RAW_PART also.
* Change another use of the unit number to a softc pointer.
* Use a dkdevice to hold the label and open partition masks.
* Force the partition offset to 0 for RAW_PART, regardless of the label.
* Nuke MCDPHYS() and MCDREADRAW; they had a silly bug that caused the code
to not work, and they aren't useful anyway.
Some other minor cleanup.
mycroft