usb: dwc3: Fix the dwc3 dependency

The warning shown up when ran with randconfig,

warning: (USB_DWC3) selects USB_XHCI_PLATFORM which has unmet direct dependencies (USB_SUPPORT && USB_XHCI_HCD)

Signed-off-by: joseph daniel <josephdanielwalter@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>