ASoC: dt-bindings: fsl,imx-asrc: Document audio graph port

This device can be used in conjunction with audio-graph-card to provide
an endpoint for binding with the other side of the audio link.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: "Rob Herring (Arm)" <robh@kernel.org>
Link: https://patch.msgid.link/20250306053138.1914956-1-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl,imx-asrc.yaml

@@ -77,6 +77,10 @@ properties:
   power-domains:
     maxItems: 1
 
+  port:
+    $ref: audio-graph-port.yaml#
+    unevaluatedProperties: false
+
   fsl,asrc-rate:
     $ref: /schemas/types.yaml#/definitions/uint32
     description: The mutual sample rate used by DPCM Back Ends
@@ -174,4 +178,12 @@ examples:
                     "txa", "txb", "txc";
         fsl,asrc-rate  = <48000>;
         fsl,asrc-width = <16>;
+
+        port {
+            playback-only;
+
+            asrc_endpoint: endpoint {
+                remote-endpoint = <&fe00_ep>;
+            };
+       };
     };