Shift to using the same queueing strategy that the amr driver uses.
Some simple tests indicate that we use about 2% of the CPU at around
500tps with the controller completely saturated with I/O.
PJ cards. This will probably also support the AcceleRAID and
eXtremeRAID cards, but nobody has volunteered one for testing, so I
haven't enabled their PCI device IDs.
Slightly clean up communication between the disk devices and the
controller device as per new practice, and move some more register-
related items int mlxreg.h from mlxvar.h.
Remove some unnecessary read-modify-write operations to the card
control registers; they don't behave like that.
Increase the status polling interval to 10 seconds. It's still possible
to load the card up to the point where a status poll will find the
previous poll still running, but this will reduce the incidence of
complaints.
