vernee-k506: new device

Works: booting, USB internet, display, touchscreen, physical buttons.

Regarding UIs: xfce4 freezes and reboots, weston seems fine in the logs but doesnt display the desktop. sxmo works.

kernel source from https://github.com/MediatekAndroidDevelopers/android_kernel_vernee_thor_k506

they also have the vendor blobs which may be salvageable https://github.com/MediatekAndroidDevelopers/android_vendor_vernee_thor_k506