touchpad: disable the pressure axes wherever the resolution is nonzero
The kernel/udev set the pressure resolution to nonzero to indicate the value is in a known scale (units/g). We use that information to disable the pressure axis on such devices - real pressure cannot be translated to contact size.
For the kernel patch see: https://www.spinics.net/lists/linux-input/msg71237.html
Fixes #569 (closed)