Add a Device Tree node to support the LED-backed "menu" and "back" keys.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20231206221556.15348-3-paul@crapouillou.netSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>