ASoC: dt-bindings: atmel,at91-ssc: add microchip,sam9x7-ssc

Add microchip,sam9x7-ssc to DT bindings documentation.

Signed-off-by: Varshini Rajendran <varshini.rajendran@microchip.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250610065005.64070-1-varshini.rajendran@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: varshini-rajendran

Documentation/devicetree/bindings/sound/atmel,at91-ssc.yaml

@@ -16,9 +16,14 @@ description:
 
 properties:
   compatible:
-    enum:
-      - atmel,at91rm9200-ssc
-      - atmel,at91sam9g45-ssc
+    oneOf:
+      - enum:
+          - atmel,at91rm9200-ssc
+          - atmel,at91sam9g45-ssc
+      - items:
+          - enum:
+              - microchip,sam9x7-ssc
+          - const: atmel,at91sam9g45-ssc
 
   reg:
     maxItems: 1