usb: gadget: uvc: dont call usb_composite_setup_continue when not streaming

usb: gadget: uvc: dont call usb_composite_setup_continue when not streaming

If the streamoff call was triggered by some previous disconnect
or userspace application shutdown the uvc_function_setup_continue
should not be called and the state should not be overwritten.

For this situation the set_alt(0) was never called and the streaming ep
has no USB_GADGET_DELAYED_STATUS pending.

Since the state then was already updated before we also omit the state
update.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-9-e224bb1035f0@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>