motorola-montana: use aarch64

So, @kubast2 deleted his/her kernel fork and told us to use this kernel from unofficial LineageOS team (see #271 (closed)). This MR uses that kernel, and as bonus, makes pmOS port for motorola-montana aarch64, as that kernel is aarch64. Unfortunately, touchscreen doesn't work, but i might fix this in other MR, which may include other various improvements (such as WiFi, audio, etc.). Also I edited wiki page to represent this MR.

Edit by PureTryOut: This closes #271 (closed)