I finally found some time to hack the depca driver, in basically the
same way I did with the de4x5 driver. The patch is quite big (shuffles
a lot of code around, removes lots of global variables), mainly in
order to use the driver model on every bus supported by this driver.

I also removed the probing from Space.c, so the usual warning about
device renumbering applies.

Tested on alpha (DE422, EISA) and i386 (two DE201, ISA), built-in and
modular. The MCA part is completly untested, since I lack the hardware
(no, I do not own every single piece of junk hardware out
there... ;-).