main/postmarketos-base: modify tm2-touchkey udev rule for midas

PMA!2926 introduced touchkey functionality for midas devices (Exynos 4412 based Samsung Galaxy S III and Note II devices), however, due to hardware variants in the touchkeys, the keys are reversed. This amends the udev rules to ensure the non-midas devices have their configuration and the midas devices have theirs use the default configuration.

See my comments on closed issue PMA#1422.