[NET]: Do not protect sysctl_optmem_max with CONFIG_SYSCTL

The ipv4 and ipv6 protocols need to access it unconditionally.
SYSCTL=n build failure reported by Russell King.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index cf62826..8c48fbe 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1377,9 +1377,10 @@
 
 #ifdef CONFIG_SYSCTL
 extern struct ctl_table core_table[];
-extern int sysctl_optmem_max;
 #endif
 
+extern int sysctl_optmem_max;
+
 extern __u32 sysctl_wmem_default;
 extern __u32 sysctl_rmem_default;