usb: dwc2: gadget: Use hw params from core

Use the previously cached hw params in the gadget. This saves a reset
and force mode in the gadget initialization during probe and makes
getting the hardware parameters consistent between gadget and host.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>