dt-bindings: clock: qcom: Allow VDD_GFX supply to GX

In some designs the SoC's VDD_GFX pads are supplied by an external
regulator, rather than a power-domain. Allow this to be described in the
GPU clock controller binding.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20240125-sa8295p-gpu-v4-1-7011c2a63037@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Documentation/devicetree/bindings/clock/qcom,gpucc.yaml

@@ -53,6 +53,9 @@ properties:
   power-domains:
     maxItems: 1
 
+  vdd-gfx-supply:
+    description: Regulator supply for the VDD_GFX pads
+
   '#clock-cells':
     const: 1
 
@@ -74,6 +77,12 @@ required:
   - '#reset-cells'
   - '#power-domain-cells'
 
+# Require that power-domains and vdd-gfx-supply are not both present
+not:
+  required:
+    - power-domains
+    - vdd-gfx-supply
+
 additionalProperties: false
 
 examples: