dt-bindings: rng: atmel,at91-trng: document sama7g5 TRNG

Add compatbile for Microchip sama7g5 TRNG.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211227183251.132525-3-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/rng/atmel,at91-trng.yaml

@@ -13,9 +13,14 @@ maintainers:
 
 properties:
   compatible:
-    enum:
+    oneOf:
+      - enum:
           - atmel,at91sam9g45-trng
           - microchip,sam9x60-trng
+      - items:
+          - enum:
+              - microchip,sama7g5-trng
+          - const: atmel,at91sam9g45-trng
 
   clocks:
     maxItems: 1