dt-bindings: memory-controllers: renesas,rpc-if: add top-level constraints

Properties with variable number of items per each device are expected to
have widest constraints in top-level "properties:" block and further
customized (narrowed) in "if:then:".  Add missing top-level constraints
for clocks.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240818172930.121898-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Documentation/devicetree/bindings/memory-controllers/renesas,rpc-if.yaml

@@ -67,7 +67,9 @@ properties:
       - const: dirmap
       - const: wbuf
 
-  clocks: true
+  clocks:
+    minItems: 1
+    maxItems: 2
 
   interrupts:
     maxItems: 1