fotg210-udc: Add missing completion handler

This is used when responding to GET_STATUS requests. Without this, it
crashes on completion.

Fixes: b84a8dee ("usb: gadget: add Faraday fotg210_udc driver")
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230123073508.2350402-2-linus.walleij@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>