ASoC: dt-bindings: fsl_spdif: Document imx6sl/sx compatible fallback

i.MX6SL and i.MX6SX SPDIF blocks are compatible with i.MX35.

Document 'fsl,imx35-spdif' as a fallback compatible for these two
chip variants.

This fixes the following dt-schema warnings:

compatible: ['fsl,imx6sl-spdif', 'fsl,imx35-spdif'] is too long
compatible: ['fsl,imx6sx-spdif', 'fsl,imx35-spdif'] is too long

Signed-off-by: Fabio Estevam <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/sound/fsl,spdif.yaml

···
 
 properties:
   compatible:
-    enum:
-      - fsl,imx35-spdif
-      - fsl,vf610-spdif
-      - fsl,imx6sx-spdif
-      - fsl,imx8qm-spdif
-      - fsl,imx8qxp-spdif
-      - fsl,imx8mq-spdif
-      - fsl,imx8mm-spdif
-      - fsl,imx8mn-spdif
-      - fsl,imx8ulp-spdif
+    oneOf:
+      - items:
+          - enum:
+              - fsl,imx35-spdif
+              - fsl,imx6sx-spdif
+              - fsl,imx8mm-spdif
+              - fsl,imx8mn-spdif
+              - fsl,imx8mq-spdif
+              - fsl,imx8qm-spdif
+              - fsl,imx8qxp-spdif
+              - fsl,imx8ulp-spdif
+              - fsl,vf610-spdif
+      - items:
+          - enum:
+              - fsl,imx6sl-spdif
+              - fsl,imx6sx-spdif
+          - const: fsl,imx35-spdif
 
   reg:
     maxItems: 1