drivers: udc: add initial support for DWC2 controller

The driver currently supports only dedicated FIFO mode (with
dynfifosizing if enabled). Control, bulk and interrupt transfers are
supported, isochronous transfers are not yet supported. The driver
accesses controller registers using sys_io.h, but for debugging purposes
one can get a register map from the driver's config, similar to the
usb_dc_dw.c driver.

Initial support also has vendor quirks for the STM32F4 SoC family.
Tested on NUCLEO-F413HG.

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