usb: gadget: Add bcdDevice for the MTU3 USB Gadget Controller

Add an entry in usb_gadget_controller_number() for the MTU3
gadget controller. It is used to bind the USB Ethernet driver.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>