Input: psmouse - disable changing resolution/rate/scale for FocalTech

Input: psmouse - disable changing resolution/rate/scale for FocalTech

These PS/2 commands make some touchpads stop responding, so this commit
adds some dummy functions to replace the generic implementation. Because
scale changes were not encapsulated in a method of struct psmouse yet, this
commit adds a method set_scale to psmouse.

Signed-off-by: Mathias Gottschlag <mgottschlag@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>