[NET]: Fix sparse warnings

Of this type, mostly:

CHECK   net/ipv6/netfilter.c
net/ipv6/netfilter.c:96:12: warning: symbol 'ipv6_netfilter_init' was not declared. Should it be static?
net/ipv6/netfilter.c:101:6: warning: symbol 'ipv6_netfilter_fini' was not declared. Should it be static?

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index a3ed53c..c01511e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -267,10 +267,6 @@
 	spin_unlock_bh(&ptype_lock);
 }
 
-extern void linkwatch_run_queue(void);
-
-
-
 /**
  *	__dev_remove_pack	 - remove packet handler
  *	@pt: packet type declaration
@@ -1133,8 +1129,6 @@
 #define illegal_highdma(dev, skb)	(0)
 #endif
 
-extern void skb_release_data(struct sk_buff *);
-
 /* Keep head the same: replace data */
 int __skb_linearize(struct sk_buff *skb, unsigned int __nocast gfp_mask)
 {
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 8f817ad..2f278c8 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -9,23 +9,18 @@
 #include <linux/sysctl.h>
 #include <linux/config.h>
 #include <linux/module.h>
+#include <linux/socket.h>
+#include <net/sock.h>
 
 #ifdef CONFIG_SYSCTL
 
 extern int netdev_max_backlog;
-extern int netdev_budget;
 extern int weight_p;
-extern int net_msg_cost;
-extern int net_msg_burst;
 
 extern __u32 sysctl_wmem_max;
 extern __u32 sysctl_rmem_max;
-extern __u32 sysctl_wmem_default;
-extern __u32 sysctl_rmem_default;
 
 extern int sysctl_core_destroy_delay;
-extern int sysctl_optmem_max;
-extern int sysctl_somaxconn;
 
 #ifdef CONFIG_NET_DIVERT
 extern char sysctl_divert_version[];
diff --git a/net/core/utils.c b/net/core/utils.c
index 88eb8b6..7b5970f 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -16,7 +16,9 @@
 #include <linux/module.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
+#include <linux/inet.h>
 #include <linux/mm.h>
+#include <linux/net.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/random.h>
diff --git a/net/core/wireless.c b/net/core/wireless.c
index 19fa6a5..5caae23 100644
--- a/net/core/wireless.c
+++ b/net/core/wireless.c
@@ -571,10 +571,6 @@
 	return 0;
 }
 
-extern void *dev_seq_start(struct seq_file *seq, loff_t *pos);
-extern void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos);
-extern void dev_seq_stop(struct seq_file *seq, void *v);
-
 static struct seq_operations wireless_seq_ops = {
 	.start = dev_seq_start,
 	.next  = dev_seq_next,