staging: usbip: Renaming pr_warning function

Eliminated the following warning "WARNING: Prefer pr_warn(... to
pr_warning(...)" by renaming the pr_warning function to pr_warn in
usbip_event.c file.
Signed-off-by: Lisa Nguyen <lisa@xenapiadmin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/usbip/usbip_event.c

@@ -85,7 +85,7 @@ int usbip_start_eh(struct usbip_device *ud)
 
 	ud->eh = kthread_run(event_handler_loop, ud, "usbip_eh");
 	if (IS_ERR(ud->eh)) {
-		pr_warning("Unable to start control thread\n");
+		pr_warn("Unable to start control thread\n");
 		return PTR_ERR(ud->eh);
 	}