ASoC: dt-bindings: Use OF graph schema

Now that we have an OF graph schema, let's use it for the
audio-graph-port schema.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210331142748.2163272-3-robh@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/audio-graph-port.yaml

@@ -11,9 +11,10 @@ maintainers:
 
 select: false
 
+allOf:
+  - $ref: /schemas/graph.yaml#/$defs/port-base
+
 properties:
-  reg:
-    maxItems: 1
   prefix:
     description: "device name prefix"
     $ref: /schemas/types.yaml#/definitions/string
@@ -25,10 +26,8 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
 patternProperties:
   "^endpoint(@[0-9a-f]+)?":
-    type: object
+    $ref: /schemas/graph.yaml#/$defs/endpoint-base
     properties:
-      remote-endpoint:
-        maxItems: 1
       mclk-fs:
         description: |
           Multiplication factor between stream rate and codec mclk.