drivers: udc_dwc2: Fix large control write transfers

The DOEPTSIZ0 XferSize field is 7 bits long, meaning that maximum single
transfer can be 127 bytes long. Configure the control write (OUT)
transfers considering the XferSize field size to support transfers with
data stage larger than 127 bytes.

Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>