dt-bindings: mmc: mtk-sd: Add support for Dimensity 1200 MT6893

Add a compatible for the MediaTek Dimensity 1200 (MT6893) SoC.
All of the MMC/SD controllers in this chip are compatible with
the ones found in MT8183, but do also make use of an optional
crypto clock when enabling HW disk encryption.

Signed-off-by: AngeloGioacchino Del Regno <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

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

···
           - const: mediatek,mt2701-mmc
       - items:
           - enum:
+              - mediatek,mt6893-mmc
               - mediatek,mt8186-mmc
               - mediatek,mt8188-mmc
               - mediatek,mt8192-mmc
···
       properties:
         compatible:
           enum:
+            - mediatek,mt6893-mmc
             - mediatek,mt8186-mmc
             - mediatek,mt8188-mmc
             - mediatek,mt8195-mmc