dt-bindings: arm: mediatek: mmsys: add support for MT8186

Add "mediatek,mt8186-mmsys" to binding document.
Signed-off-by: NRex-BC Chen <rex-bc.chen@mediatek.com>
Acked-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220301080105.31323-2-rex-bc.chen@mediatek.comSigned-off-by: NMatthias Brugger <matthias.bgg@gmail.com>

Documentation/devicetree/bindings/arm/mediatek/mediatek,mmsys.yaml

@@ -29,6 +29,7 @@ properties:
               - mediatek,mt8167-mmsys
               - mediatek,mt8173-mmsys
               - mediatek,mt8183-mmsys
+              - mediatek,mt8186-mmsys
               - mediatek,mt8192-mmsys
               - mediatek,mt8365-mmsys
           - const: syscon