drivers: input: touch_disabler: Update getter/setter logic

 * Add checks to code to allow variables to be modified via
   sysfs iff the corresponding input_dev type for the touch
   device is set.

 * Also return false in "enabled" and "auto" in control if
   the corresponding input_dev for the touch device is not set.

Change-Id: Icd3622e608b42d67918cf1685f9905456585b501