FBK kernel config requirement

Some kernel config required

• USB CONFIG FS need be built-in

• One of UDC driver and PHY need be built-in

• Function FS need be enabled

      Device Drivers
      USB support
             USB gadget support (very last entry)
                    USB Gadget Drivers (...)
                           USB functions configurable through configfs
                                  Mass storage
                                  Function filesystem (functionFS)