dt-bindings: leds: Add binding for AW200xx

Add YAML devicetree binding for AWINIC AW20036/AW20052/AW20074
led driver.

Signed-off-by: Martin Kurbanov <mmkurbanov@sberdevices.ru>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230519130403.212479-2-mmkurbanov@sberdevices.ru


Signed-off-by: Lee Jones <lee@kernel.org>