ASoC: dt-bindings: renesas,rsnd: add missing playback/capture

renesas,rsnd.yaml is possible to use ports/port/endpoint if it is using
Audio Graph Card/Card2 for sound. The schema is defined under
audio-graph-port.yaml.

rsnd driver needs "playback/capture" property under endpoint, but it is not
defined in audio-graph-port.yaml. This patch adds missing "playback/capture"
properties under endpoint.

Without this patch, we will get below warning

${LINUX}/arch/arm64/boot/dts/renesas/r8a77950-salvator-x.dtb: sound@ec500000: ports:port@0:endpoint: Unevaluated properties are not allowed ('playback', 'capture' were unexpected)
	From schema: ${LINUX}/Documentation/devicetree/bindings/sound/renesas,rsnd.yaml

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87h6wh7rfj.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/renesas,rsnd.yaml

@@ -109,15 +109,34 @@ properties:
         - pattern: '^clk_(a|b|c|i)$'
 
   ports:
-    $ref: /schemas/graph.yaml#/properties/ports
+    $ref: audio-graph-port.yaml#/definitions/port-base
+    unevaluatedProperties: false
     patternProperties:
       '^port(@[0-9a-f]+)?$':
-        $ref: audio-graph-port.yaml#
+        $ref: audio-graph-port.yaml#/definitions/port-base
         unevaluatedProperties: false
+        patternProperties:
+          "^endpoint(@[0-9a-f]+)?":
+            $ref: audio-graph-port.yaml#/definitions/endpoint-base
+            properties:
+              playback:
+                $ref: /schemas/types.yaml#/definitions/phandle-array
+              capture:
+                $ref: /schemas/types.yaml#/definitions/phandle-array
+            unevaluatedProperties: false
 
   port:
-    $ref: audio-graph-port.yaml#
+    $ref: audio-graph-port.yaml#/definitions/port-base
     unevaluatedProperties: false
+    patternProperties:
+      "^endpoint(@[0-9a-f]+)?":
+        $ref: audio-graph-port.yaml#/definitions/endpoint-base
+        properties:
+          playback:
+            $ref: /schemas/types.yaml#/definitions/phandle-array
+          capture:
+            $ref: /schemas/types.yaml#/definitions/phandle-array
+        unevaluatedProperties: false
 
   rcar_sound,dvc:
     description: DVC subnode.