* Update default Nyquist revision
* LED slave fix
* Sync changes from lets_split
* Add needed check for debouncing
* Remove line that was setting PD2 pin and interfering with use of that pin
* Add backlight key to keymap
* Account for backlight enabled flag when passing backlight level to slave
* Add BL_TOGG to keymap for testing
* Apply backlight fix to Iris
* Port I2C LED backlight control from Iris to Levinson