ARM: dts: qcom: sdx55: Add USB3 and PHY support

Add devicetree nodes for enabling USB3 controller, Qcom QMP PHY and
SNPS HS PHY on SDX55.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210118051005.55958-3-manivannan.sadhasivam@linaro.org
[bjorn: Added missing #power-domain-cells to &gcc]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>