UART and SSH work and HDMI works in u-boot (just like the pine-a64lts).
It should work now with display and xorg/weston works directly after
installing. Plasma mobile doesn't work directly because both kms and
fbdev are enabled and kms doesn't work yet.
linux-postmarketos-allwinner: update to 5.0.0-rc3 with patches for this
devkit, tested on this device and on pinea64lts (the only other device
using the allwinner kernel).
[ci:skip-build]: won't finish in time
