PinePhone: Added seperate images for long/short touchscreen

This adds a seperate dts for the longts version of the devkit (which was the un-inverted version before) and adds a shortts version which was inverted before, but didn't exist in pmaports yet because I manually edited the dts for every release.

This MR abuses the kernel switching feature to switch the dtb instead so shortts/longts can be selected in the init step.