netns: Use net_eq() to compare net-namespaces for optimization.

Without CONFIG_NET_NS, namespace is always &init_net.
Compiler will be able to omit namespace comparisons with this patch.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 033c712..c519b8d 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1124,7 +1124,7 @@
 	struct vif_device *v;
 	int ct;
 
-	if (dev_net(dev) != &init_net)
+	if (!net_eq(dev_net(dev), &init_net))
 		return NOTIFY_DONE;
 
 	if (event != NETDEV_UNREGISTER)