dt-bindings: soc: mediatek: Add mdp3 mutex support for mt8186

Add mdp3 mutex compatible for mt8186 SoC.

Co-developed-by: Xiandong Wang <xiandong.wang@mediatek.com>
Signed-off-by: Xiandong Wang <xiandong.wang@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220831172151.10215-2-allen-kh.cheng@mediatek.com


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