phy: qcom-qmp: Add support for SDX55 QMP PCIe PHY

The PCIe PHY version used in SDX55 is v4.20 which has different register
offsets compared to the v4.0x PHYs. So separate register defines are
used for init sequence.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>