ASoC: dt-bindings: rockchip-spdif: Allow "port" node

Add a "port" node entry for Rockchip S/PDIF binding. It's already in use
and a common property for DAIs.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260108224938.1320809-1-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: robherring

Documentation/devicetree/bindings/sound/rockchip-spdif.yaml

@@ -70,6 +70,9 @@ properties:
   "#sound-dai-cells":
     const: 0
 
+  port:
+    $ref: /schemas/graph.yaml#/properties/port
+
 required:
   - compatible
   - reg