[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>

net/ipv4/Makefile

@@ -10,9 +10,10 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     tcp_minisocks.o tcp_cong.o \
 	     datagram.o raw.o udp.o udplite.o \
 	     arp.o icmp.o devinet.o af_inet.o  igmp.o \
-	     sysctl_net_ipv4.o fib_frontend.o fib_semantics.o \
+	     fib_frontend.o fib_semantics.o \
 	     inet_fragment.o
 
+obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o
 obj-$(CONFIG_IP_FIB_HASH) += fib_hash.o
 obj-$(CONFIG_IP_FIB_TRIE) += fib_trie.o
 obj-$(CONFIG_PROC_FS) += proc.o