usb: gadget: uvc: wake pump everytime we update the free list

Since the req_free list will updated if enqueuing one request was not
possible it will be added back to the free list. With every available
free request in the queue it is a valid case for the pump worker to use
it and continue the pending bufferdata into requests for the req_ready
list.

Fixes: 6acba03 ("usb:gadget:uvc Do not use worker thread to pump isoc usb requests")
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-1-e224bb1035f0@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/uvc_video.c

@@ -480,6 +480,10 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 		 * up later.
 		 */
 		list_add_tail(&to_queue->list, &video->req_free);
+		/*
+		 * There is a new free request - wake up the pump.
+		 */
+		queue_work(video->async_wq, &video->pump);
 	}
 
 	spin_unlock_irqrestore(&video->req_lock, flags);