dt-bindings: power: fsl,imx-gpc: Document address-cells

The GPC power controller is an interrupt controllers and can be referenced
in interrupt-map properties, e.g. PCIe controller, thus the node should
have address-cells property.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: tq-steina

Documentation/devicetree/bindings/power/fsl,imx-gpc.yaml

@@ -38,6 +38,9 @@ properties:
   reg:
     maxItems: 1
 
+  "#address-cells":
+    const: 0
+
   interrupts:
     maxItems: 1