usb: gadget: uvc: set v4l2_dev->dev in f_uvc

The v4l2_dev has no corresponding device to it. We will
point it to the gadget's dev.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20210628155311.16762-4-m.grzeschik@pengutronix.de


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