xorg: drop the custom motion scaling, use the server's instead

The server has all sorts of crazy scaling to make sure the device motion
corresponds to something sane on the screen. Use that while we have it rather
than invent our own.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
xorg: slow down the pointer by factor 6

Should probably revert this once we have something better (and dependent on
the HW) but for now it'll at least make my device usable.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Add helper function for a touch reset

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>