default values after probing

This sets the mouse to 100 samples/second, 200 dpi, 1:1 mapping, which
is a standard setting, as close to 2.4 XFree86 behavior as possible, and
a good performance setting, too. 

It also in the case of 'psmouse_noext' doesn't probe and set anything
all, though it still issues the RESET command. This is as safe as one
can get.

The only real problem remaining is that the report rate and resolution
cannot be set from XFree86 config and only is available as a
kernel/module parameter. The fix is, howewer not 2.6.0 material.