dt-bindings: power: mediatek: Support naming power controller node with unit address

Support naming power controller node with unit address, also compatible
with node names without unit address.

Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220729063208.16799-5-tinghan.shen@mediatek.com


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