dt-bindings: display: mediatek: dpi: Add power domains

Add power domain binding to the mediatek DPI controller
for MT8186.
Also, add power domain binding for other SoCs like
MT6795 and MT8173 that already had power domain property.

Signed-off-by: Rohit Agarwal <rohiagar@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240830084544.2898512-2-rohiagar@chromium.org/


Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>