mac80211: Convert call_rcu() to kfree_rcu(), drop mesh_gate_node_reclaim()

The call_rcu() in mesh_gate_del() invokes mesh_gate_node_reclaim(),
which simply calls kfree().  So convert the call_rcu() to kfree_rcu(),
allowing mesh_gate_node_reclaim() to be eliminated.
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org

net/mac80211/mesh_pathtbl.c

@@ -413,12 +413,6 @@ struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data
 	return NULL;
 }
 
-static void mesh_gate_node_reclaim(struct rcu_head *rp)
-{
-	struct mpath_node *node = container_of(rp, struct mpath_node, rcu);
-	kfree(node);
-}
-
 /**
  * mesh_path_add_gate - add the given mpath to a mesh gate to our path table
  * @mpath: gate path to add to table
@@ -479,7 +473,7 @@ static int mesh_gate_del(struct mesh_table *tbl, struct mesh_path *mpath)
 		if (gate->mpath == mpath) {
 			spin_lock_bh(&tbl->gates_lock);
 			hlist_del_rcu(&gate->list);
-			call_rcu(&gate->rcu, mesh_gate_node_reclaim);
+			kfree_rcu(gate, rcu);
 			spin_unlock_bh(&tbl->gates_lock);
 			mpath->sdata->u.mesh.num_gates--;
 			mpath->is_gate = false;