Draft: radxa-zero: new device

radxa-zero booting mainline. usb-network doesnt seem to be working, but usb works, wifi works with firmware extracted from armbian, display works, but gnome seems to crash immediately.

currently booting with u-boot from armbian flashed to mmcblk1boot0. tow-boot supports the zero2, so maybe a port to the zero can come soon?

also i tried using just linux-edge and it wouldnt boot, so linux-radxa-zero is just mainline with a config that boots. should i rename it to something more generic?