samples: cdc_acm: add DT overlay to support snps,dwc2 on nucleo_f413zh

Add DT overlay to be able to support and test usb_dc_dw driver
(snps,dwc2) on nucleo_f413zh board. This disables STM32 shim
driver described and configured on the SoC and board level.

Obviously,it works with other STM32F4 boards as well, but we
do not have a mechanism to apply it generically yet, upcoming
snippet support may fix that. Until then, we need something for
development and as an example.

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