tipc: make tipc node table aware of net namespace

Global variables associated with node table are below:
- node table list (node_htable)
- node hash table list (tipc_node_list)
- node table lock (node_list_lock)
- node number counter (tipc_num_nodes)
- node link number counter (tipc_num_links)

To make node table support namespace, above global variables must be
moved to tipc_net structure in order to keep secret for different
namespaces. As a consequence, these variables are allocated and
initialized when namespace is created, and deallocated when namespace
is destroyed. After the change, functions associated with these
variables have to utilize a namespace pointer to access them. So
adding namespace pointer as a parameter of these functions is the
major change made in the commit.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Tested-by: Tero Aho <Tero.Aho@coriant.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/discover.c

@@ -162,9 +162,9 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
 		return;
 
 	/* Locate, or if necessary, create, node: */
-	node = tipc_node_find(onode);
+	node = tipc_node_find(net, onode);
 	if (!node)
-		node = tipc_node_create(onode);
+		node = tipc_node_create(net, onode);
 	if (!node)
 		return;