dt-bindings: interrupt-controller: Allow #power-domain-cells

MPM provides a single genpd. Allow #power-domain-cells = <0>.

Fixes: 54fc9851c0e0 ("dt-bindings: interrupt-controller: Add Qualcomm MPM support")
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20231129-topic-mpmbindingspd-v2-1-acbe909ceee1@linaro.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/interrupt-controller/qcom,mpm.yaml

@@ -62,6 +62,9 @@ properties:
         - description: MPM pin number
         - description: GIC SPI number for the MPM pin
 
+  '#power-domain-cells':
+    const: 0
+
 required:
   - compatible
   - reg
@@ -93,4 +96,5 @@ examples:
                            <86 183>,
                            <90 260>,
                            <91 260>;
+        #power-domain-cells = <0>;
     };