Extcon for USB C

Use extcon to communicate between all of the various USB C parts.

This has been tested by me and @sebastian.krzyszkowiak but I'd like to get it checked with some other workflows before merging this.

I've been using the latest tps65982 firmware for this testing ( use the 5V firmware for Birch and Chestnut ) https://source.puri.sm/Librem5/firmware-tps6598x-nonfree/-/blob/master/tps65982-librem5-dp-alt-mode.bin

This should work on Birch or Chestnut as well as long as you have at least 1 working CC line and you apply power for external hubs.

To help debug you can enable dynamic debug statements

echo 'file drivers/power/supply/bq25890_charger.c  +p' | sudo tee /sys/kernel/debug/dynamic_debug/control
echo 'file drivers/usb/typec/tps6598x.c  +p' | sudo tee /sys/kernel/debug/dynamic_debug/control
echo 'file drivers/dwc3/* +p' | sudo tee /sys/kernel/debug/dynamic_debug/control