dt-bindings: phy: qcom,qmp-usb: add missing power-domains property

At least the "sc8280xp-qmp-usb3-uni-phy" binding requires a power domain
to be specified.

Fixes: aa27597e59 ("dt-bindings: phy: qcom,qmp: Add compatible for SC8280XP USB phys")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220902080705.12050-2-johan+linaro@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/qcom,qmp-usb-phy.yaml

@@ -58,6 +58,9 @@ properties:
     minItems: 3
     maxItems: 4
 
+  power-domains:
+    maxItems: 1
+
   resets:
     maxItems: 2
 
@@ -265,6 +268,16 @@ allOf:
             - const: phy_phy
             - const: phy
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,sc8280xp-qmp-usb3-uni-phy
+    then:
+      required:
+        - power-domains
+
   - if:
       properties:
         compatible: