dt-bindings: mmc: Add compatible for MediaTek MT8188

This commit adds dt-binding documentation of mmc for MediaTek MT8188 SoC
platform.

Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220708114747.13878-1-johnson.wang@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: Johnson Wang

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

@@ -30,13 +30,11 @@ properties:
           - 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
-      - items:
-          - const: mediatek,mt8195-mmc
+          - enum:
+              - mediatek,mt8186-mmc
+              - mediatek,mt8188-mmc
+              - mediatek,mt8192-mmc
+              - mediatek,mt8195-mmc
           - const: mediatek,mt8183-mmc
 
   reg: