dt-bindings: interrupt-controller: marvell,cp110-icu: Document address-cells

The CP110 ICU children are interrupt controllers and can be referenced
in interrupt-map properties (e.g. in
arch/arm64/boot/dts/marvell/armada-cp11x.dtsi), thus the nodes should
have address-cells property.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring (Arm) <[e-mail]>

Documentation/devicetree/bindings/interrupt-controller/marvell,cp110-icu.yaml

···
       reg:
         maxItems: 1
 
+      '#address-cells':
+        const: 0
+
       '#interrupt-cells':
         const: 2