dt-bindings: watchdog: sama5d4-wdt: add compatible for sam9x7-wdt

Add compatible microchip,sam9x7-wdt to DT bindings documentation.
Signed-off-by: Varshini Rajendran <varshini.rajendran@microchip.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240223172627.672316-1-varshini.rajendran@microchip.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Documentation/devicetree/bindings/watchdog/atmel,sama5d4-wdt.yaml

@@ -14,10 +14,14 @@ allOf:
 
 properties:
   compatible:
-    enum:
-      - atmel,sama5d4-wdt
-      - microchip,sam9x60-wdt
-      - microchip,sama7g5-wdt
+    oneOf:
+      - enum:
+          - atmel,sama5d4-wdt
+          - microchip,sam9x60-wdt
+          - microchip,sama7g5-wdt
+      - items:
+          - const: microchip,sam9x7-wdt
+          - const: microchip,sam9x60-wdt
 
   reg:
     maxItems: 1