phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips

PHY transceiver driver for QUSB2 phy controller that provides
HighSpeed functionality for DWC3 controller present on
Qualcomm chipsets.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>