usb: gadget: Refactor request completion

Use the recently introduced usb_gadget_giveback_request() in favor of
direct invocation of the completion routine.

All places in drivers/usb/ matching "[-.]complete(" were replaced with a
call to usb_gadget_giveback_request(). This was compile-tested with all
ARM drivers enabled and runtime-tested for musb.

Signed-off-by: Michal Sojka <sojka@merica.cz>
Acked-by: Felipe Balbi <balbi@ti.com>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/s3c-hsudc.c

@@ -258,8 +258,7 @@ static void s3c_hsudc_complete_request(struct s3c_hsudc_ep *hsep,
 
 	hsep->stopped = 1;
 	spin_unlock(&hsudc->lock);
-	if (hsreq->req.complete != NULL)
-		hsreq->req.complete(&hsep->ep, &hsreq->req);
+	usb_gadget_giveback_request(&hsep->ep, &hsreq->req);
 	spin_lock(&hsudc->lock);
 	hsep->stopped = stopped;
 }