dt-bindings: phy: mediatek: dsi-phy: modify compatible dependence

mt7623-mipi-tx is compatible to mt2701-mipi-tx, and use
"mediatek,mt2701-mipi-tx" instead on MT7623, so modify
the compatible items to make dependence clear.

Cc: Chun-Kuang Hu <[e-mail]>
Cc: Philipp Zabel <[e-mail]>
Acked-by: Chun-Kuang Hu <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Chunfeng Yun <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/phy/mediatek,dsi-phy.yaml

···
     pattern: "^dsi-phy@[0-9a-f]+$"
 
   compatible:
-    enum:
-      - mediatek,mt2701-mipi-tx
-      - mediatek,mt7623-mipi-tx
-      - mediatek,mt8173-mipi-tx
-      - mediatek,mt8183-mipi-tx
+    oneOf:
+      - items:
+          - enum:
+              - mediatek,mt7623-mipi-tx
+          - const: mediatek,mt2701-mipi-tx
+      - const: mediatek,mt2701-mipi-tx
+      - const: mediatek,mt8173-mipi-tx
+      - const: mediatek,mt8183-mipi-tx
 
   reg:
     maxItems: 1