usb: dwc3: Add Qualcomm DWC3 compatible string

Lot of Qualcomm SoC-s use DWC3 controller for both USB2.0 and USB3.0
ports.
Qualcomm has some custom config registers on top of the generic ones,
but for host mode these are not needed.

So lets add the neccessary compatible string.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>