drm/mediatek: Add display merge mute/unmute support for MT8195

drm/mediatek: Add display merge mute/unmute support for MT8195

Add merge mute/unmute setting for MT8195.
MT8195 Vdosys1 merge1~merge4 support HW mute function.

Signed-off-by: Nancy.Lin <nancy.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220620091930.27797-7-nancy.lin@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>