Switch motorola-potter to linux-postmarketos-qcom-msm8953

This mr switches potter (finally) to the mailine-ish kernel for msm8953 devices. Right now display, touch, wifi and audio work as expected. USB networking also works. Battery level reporting works (but not charging). I've tested phosh and plamo, both work nicely. I've updated the wiki, hopefully I'll have modem also working soon (it requires IPAv2 which isn't supported on mainline (yet))