community/firmware-analogix: add new firmware

This adds firmware for the ANX7688 chip used in the PinePhone.

All PinePhone (from 1.0 - 1.2a) are flashed with a factory test firmware, this firmware cannot be used outside the test chamber. This APKBUILD adds the new firmware, so you can flash it with the following command:

# echo 1 > /sys/class/typec/port0/device/flash_eeprom

But another unfortunate thing is most PinePhone (except 1.2a and future revisions) has CC-pins being grounded, so you need to desolder two VCONN switches in order to take advantage of this.

More information here: https://xnux.eu/devices/feature/anx7688.html

EDIT: What should be the name of this firmware package? firmware-pine64-anx7688 maybe? Don't know if there's any device that uses ANX7688 in mobile devices except for the PinePhone.