net,rcu: convert call_rcu(kfree_tid_tx) to kfree_rcu()

The rcu callback kfree_tid_tx() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(kfree_tid_tx).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: "David S. Miller" <davem@davemloft.net>