usb: dwc3: pci: use build-in properties instead of platform data

This should allow the core driver to drop handling of
platform data and expect the platform specific details to
always come from properties.

Tested-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Huang Rui <ray.huang@amd.com>
CC: John Youn <John.Youn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>