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>