phy: qcom: Add Qualcomm PCIe2 PHY driver

The Qualcomm PCIe2 PHY is based on design from Synopsys and found in
several different platforms where the QMP PHY isn't used.

Reviewed-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>