dt-bindings: mfd: Add Apple Mac System Management Controller

Add a DT binding for the Apple Mac System Management Controller.

Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sven Peter <sven@kernel.org>
Link: https://lore.kernel.org/r/20250610-smc-6-15-v7-3-556cafd771d3@kernel.org


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