* adding rock64 board
* fix file permissions
* disable atx gpio for rock64 (breaks ethernet); restore package url; fix install
* added gpio pin definitions to config
* renamed rock64 board to generic
* udev rule for generic board, improved device detection
* this udev fix should work for most boards: it skips video0 if it's not on USB, and doesn't select video2
* cleanup
* improved usb video device selection