rockchip: Setup dwc3_device (for non-dm gadgets)

Setup dwc3_device structure for non-dm gadgets, which is used
in rk3399 platforms.

dwc3_device would have basic regbase, dr_mode, high speed
and 16-bit UTMI+ etc.

Cc: Marek Vasut <marex@denx.de>
Tested-by: Levin Du <djw@t-chip.com.cn>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
(Fix to use CONFIG_USB_DWC3_GADGET instead of CONFIG_USB_DWC3)
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>