[NET]: Remove in-code externs for some functions from net/core/dev.c

Inconsistent prototype and real type for functions may have worse
consequences, than those for variables, so move them into a header.

Since they are used privately in net/core, make this file reside in
the same place.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index f861555..f1647d7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -120,6 +120,8 @@
 #include <linux/ctype.h>
 #include <linux/if_arp.h>
 
+#include "net-sysfs.h"
+
 /*
  *	The list of packet types we will receive (as opposed to discard)
  *	and the routines to invoke.
@@ -249,10 +251,6 @@
 
 DEFINE_PER_CPU(struct softnet_data, softnet_data);
 
-extern int netdev_kobject_init(void);
-extern int netdev_register_kobject(struct net_device *);
-extern void netdev_unregister_kobject(struct net_device *);
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 /*
  * register_netdevice() inits dev->_xmit_lock and sets lockdep class