USB: make usb_unlink_urb() message only show up if CONFIG_DEBUG_KERNEL is enabled.

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/core/urb.c

@@ -451,9 +451,11 @@ int usb_unlink_urb(struct urb *urb)
 	if (!urb)
 		return -EINVAL;
 	if (!(urb->transfer_flags & URB_ASYNC_UNLINK)) {
+#ifdef CONFIG_DEBUG_KERNEL
 		printk(KERN_NOTICE "usb_unlink_urb() is deprecated for "
-			"synchronous unlinks.  Use usb_kill_urb()\n");
+			"synchronous unlinks.  Use usb_kill_urb() instead.\n");
 		WARN_ON(1);
+#endif
 		usb_kill_urb(urb);
 		return 0;
 	}