When the EP0 IN request was not completed but less than a packet sent,
it would complete the request successfully. That doesn't make sense
and can't really happen as fotg210_start_dma always sends
min(length, maxpkt) bytes.

Fixes: b84a8dee ("usb: gadget: add Faraday fotg210_udc driver")
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Link: https://lore.kernel.org/r/20210324141115.9384-4-fabian@ritter-vogt.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>