drivers: udc: add new UDC driver for SAM0 USB controller

The UDC driver for this beautiful USB controller is mostly rewritten
from scratch. USB Pad Calibration and clock handling are copied from the
usb_dc_sam0 driver.

The driver uses multipacket transfers for all endpoints except the OUT
control endpoint. The OUT control endpoint has a buffer that is always
mapped to the endpoint buffer register so that it always has a valid
buffer. The driver provides up to 7 IN and 7 OUT endpoints that support
any type of transfer. Double buffering is not used, for the possible
case of isochronous transfers some changes would be required in the
future.

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