dt-bindings: mailbox: qcom,apcs-kpss-global: fix SDX55 'if' match

The qcom,sdx55-apcs-gcc is followed by another compatible (syscon), thus
the 'if' clause must match by contains.

Fixes: 0d17014e ("dt-bindings: mailbox: Add binding for SDX55 APCS")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230322173559.809805-2-krzysztof.kozlowski@linaro.org

Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml

@@ -91,8 +91,9 @@ allOf:
   - if:
       properties:
         compatible:
-          enum:
-            - qcom,sdx55-apcs-gcc
+          contains:
+            enum:
+              - qcom,sdx55-apcs-gcc
     then:
       properties:
         clocks: