dt-bindings: mmc: Add compatible for Mediatek MT8186

This commit adds dt-binding documentation of mmc for Mediatek MT8186 SoC
Platform.
Signed-off-by: Allen-KH Cheng <Allen-KH.Cheng@mediatek.com>
Link: https://lore.kernel.org/r/20220128062050.23978-5-allen-kh.cheng@mediatek.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/mtk-sd.yaml

@@ -29,6 +29,9 @@ properties:
       - items:
           - const: mediatek,mt7623-mmc
           - const: mediatek,mt2701-mmc
+      - items:
+          - const: mediatek,mt8186-mmc
+          - const: mediatek,mt8183-mmc
       - items:
           - const: mediatek,mt8192-mmc
           - const: mediatek,mt8183-mmc