dt-bindings: riscv: cpus: Add missing additionalProperties on interrupt-controller node

The "interrupt-controller" CPU child node is missing constraints on
extra properties. Add "additionalProperties: false" to fix this.
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230915201946.4184468-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/riscv/cpus.yaml

@@ -91,6 +91,7 @@ properties:
 
   interrupt-controller:
     type: object
+    additionalProperties: false
     description: Describes the CPU's local interrupt controller
 
     properties: