[regression] PS/2 mouse support broken since 9.0

[Eugene Grosbein]

Hi!

There is PR https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=161043
about psm(4) support for PS/2 mouse broken since 2011.

Several people reported the problem. Could someone take a look at this?
I am ready to test patches as I have this problem too.
I failed to find a workaround for the problem other than stop using
PS/2 port.

Eugene Grosbein