boards: cyclonev_socdk: enable USB device controller

Currently, the usb_dc_dw driver is not enabled for any platform.
Allow to build the driver for cyclonev_socdk. Subsequent patches
will allow the driver to be used on additional platforms.
Enable USB device controller and use use new snps,dwc2 compatible.

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>