arm: socfpga: Add example UDC config

arm: socfpga: Add example UDC config

Add example of an USB UDC configuration with DFU and UMS.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Chin Liang See <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Vince Bridgers <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Cc: Stefan Roese <[email protected]>
Reviewed-by: Lukasz Majewski <[email protected]>