dt-bindings: sun6i-dsi: Add A64 DPHY compatible (w/ A31 fallback)

The MIPI DSI PHY controller on Allwinner A64 is similar
on the one on A31.

Add A64 compatible and append A31 compatible as fallback.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20191222132229.30276-3-jagan@amarulasolutions.com

Documentation/devicetree/bindings/phy/allwinner,sun6i-a31-mipi-dphy.yaml

@@ -15,7 +15,11 @@ properties:
     const: 0
 
   compatible:
-    const: allwinner,sun6i-a31-mipi-dphy
+    oneOf:
+      - const: allwinner,sun6i-a31-mipi-dphy
+      - items:
+          - const: allwinner,sun50i-a64-mipi-dphy
+          - const: allwinner,sun6i-a31-mipi-dphy
 
   reg:
     maxItems: 1