net,rcu: convert call_rcu(netlbl_unlhsh_free_addr6) to kfree_rcu()
The rcu callback netlbl_unlhsh_free_addr6() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(netlbl_unlhsh_free_addr6).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Moore <paul.moore@hp.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>