dt-bindings: phy: qcom,qmp-ufs: add missing SM8150 power domain

Add the missing optional power-domains property used by the SM8150 UFS
QMP PHY to the binding.

Fixes: fe75b0c4 ("arm64: dts: qcom: sm8150: Add ufs power-domain entries")
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20220830112923.3725-18-johan+linaro@kernel.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

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

@@ -48,6 +48,9 @@ properties:
     minItems: 1
     maxItems: 3
 
+  power-domains:
+    maxItems: 1
+
   resets:
     maxItems: 1