[IPV4]: Cleanup the sysctl_net_ipv4.c file

This includes several cleanups:

 * tune Makefile to compile out this file when SYSCTL=n. Now
   it looks like net/core/sysctl_net_core.c one;
 * move the ipv4_config to af_inet.c to exist all the time;
 * remove additional sysctl_ip_nonlocal_bind declaration
   (it is already declared in net/ip.h);
 * remove no nonger needed ifdefs from this file.

This is a preparation for using ctl paths for net/ipv4/
sysctl table.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index c75f20b..0e4b6eb 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -126,6 +126,10 @@
 static struct list_head inetsw[SOCK_MAX];
 static DEFINE_SPINLOCK(inetsw_lock);
 
+struct ipv4_config ipv4_config;
+
+EXPORT_SYMBOL(ipv4_config);
+
 /* New destruction routine */
 
 void inet_sock_destruct(struct sock *sk)