I've reworked the standard PS/2 driver to comprehend multiple mouse protocols.
In theory, with pmsi removed, this device will correctly support 3- and 5-
button mice with scroll wheels, as well as regular PS/2 mice.  It's currently
spewing debugging output, because I'm trying to track down a protocol failure
related to my KVM switch, but I could probably produce a compilable "psm.c"
for anyone who wants to play with this.

In *theory*, this will survive a change of mice between opens of the device;
unfortunately, I can't figure out what the clue is to warn us that the console
switch just changed protocols.

-s