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: aa27597e ("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>