dt-bindings: power: mediatek: Refine multiple level power domain nodes

Extract duplicated properties and support more levels of power
domain nodes.

This change fix following error when do dtbs_check,
    arch/arm64/boot/dts/mediatek/mt8195-evb.dtb: power-controller: power-domain@15:power-domain@16:power-domain@18: 'power-domain@19', 'power-domain@20', 'power-domain@21' do not match any of the regexes: 'pinctrl-[0-9]+'
	 From schema: Documentation/devicetree/bindings/power/mediatek,power-controller.yaml

Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220729063208.16799-4-tinghan.shen@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>