[NET]: netns compilation speedup

This patch speedups compilation when net_namespace.h is changed.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/pkt_cls.h

@@ -2,7 +2,6 @@
 #define __NET_PKT_CLS_H
 
 #include <linux/pkt_cls.h>
-#include <net/net_namespace.h>
 #include <net/sch_generic.h>
 #include <net/act_api.h>
 
@@ -336,6 +335,8 @@ static inline int tcf_valid_offset(const struct sk_buff *skb,
 }
 
 #ifdef CONFIG_NET_CLS_IND
+#include <net/net_namespace.h>
+
 static inline int
 tcf_change_indev(struct tcf_proto *tp, char *indev, struct rtattr *indev_tlv)
 {

include/net/sock.h

@@ -57,7 +57,6 @@
 #include <asm/atomic.h>
 #include <net/dst.h>
 #include <net/checksum.h>
-#include <net/net_namespace.h>
 
 /*
  * This structure really needs to be cleaned up.
@@ -95,6 +94,7 @@ typedef struct {
 
 struct sock;
 struct proto;
+struct net;
 
 /**
  *	struct sock_common - minimal network layer representation of sockets