Crust firmware for the PinePhone

Needs cleanup and doesn't build nicely, this can probably be entirely bypassed by just enableing or1k-elf in Alpine's gcc-cross-embedded and binutils-cross-embedded and using that compiler.

The crust package is also now build specifically for the PinePhone, this probably should be making some neat subpackages like it's done for u-boot.

Closes #550 (closed)

To test this MR, install the packages from this MR on your device, update u-boot with update-u-boot if you're not flashing a new image, and run echo mem > /sys/power/state.