net: switchdev: Fixed kerneldoc warning

Update kernel-doc line comments to fix warnings reported by make W=1.
net/switchdev/switchdev.c:413: warning: Function parameter or
member 'extack' not described in 'call_switchdev_notifiers'

Signed-off-by: Tian Tao <[email protected]>
Acked-by: Ivan Vecera <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 865f3e0..23d8685 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -404,7 +404,7 @@ EXPORT_SYMBOL_GPL(unregister_switchdev_notifier);
  *	@val: value passed unmodified to notifier function
  *	@dev: port device
  *	@info: notifier information data
- *
+ *	@extack: netlink extended ack
  *	Call all network notifier blocks.
  */
 int call_switchdev_notifiers(unsigned long val, struct net_device *dev,