phy: qcom-qusb2: Add QUSB2 PHYs support for sdm845

There are two QUSB2 PHYs present on sdm845. In order
to improve eye diagram for both the PHYs some parameters
need to be changed. Provide device tree properties to
override these from board specific device tree files.

Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>