community/xiaomi-wt88047: move from testing

The Xiaomi Redmi 2 (xiaomi-wt88047) is yet another device from the linux-postmarketos-qcom-msm8916 family that is working fairly well at this point and might as well be in community instead of testing :)

By the way, maybe we should add something like a "Suspend" feature to the table, which would make it more clear that this is one of the main remaining roadblocks for using all the MSM8916 devices as daily driver? Right now, the table really suggests that I can start using this right away as long as I don't need camera to work. :)