[NET]: Rework dev_base via list_head (v3)

Cleanup of dev_base list use, with the aim to simplify making device
list per-namespace. In almost every occasion, use of dev_base variable
and dev->next pointer could be easily replaced by for_each_netdev
loop. A few most complicated places were converted to using
first_netdev()/next_netdev().

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 35facc0..0fcf6f0 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -109,7 +109,8 @@
 	struct net_device *dev;
 	int idx;
 
-	for (dev = dev_base, idx = 0; dev; dev = dev->next) {
+	idx = 0;
+	for_each_netdev(dev) {
 		/* not a bridge port */
 		if (dev->br_port == NULL || idx < cb->args[0])
 			goto skip;