phy: qcom: Add Qualcomm PCIe PHY driver

Adding driver for the Qualcomm PCIe PHY block found paired with a
Synopsys core in some platforms.

Change-Id: I5c5da4f7dc949ff339640c0362281e2212ccd927
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Git-commit: 654376eaf1094e2ab5ad04e8113de15993f2b0b1
Git-repo: https://git.linaro.org/landing-teams/working/qualcomm/kernel.git/log/?h=niklas-qcs404-pcie2


Signed-off-by: Prashanth Vadde <pvadde@codeaurora.org>