net: ipv4: ipconfig: fix unused variable

When CONFIG_PROC_FS isn't set, variable ipconfig_dir isn't used.
net/ipv4/ipconfig.c:167:31: warning: ‘ipconfig_dir’ defined but not used [-Wunused-variable]
 static struct proc_dir_entry *ipconfig_dir;
                               ^~~~~~~~~~~~
Move the declaration of ipconfig_dir inside the CONFIG_PROC_FS ifdef to
fix the warning.

Fixes: c04d2cb2009f ("ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ipconfig.c

@@ -163,9 +163,6 @@ static u8 ic_domain[64];		/* DNS (not NIS) domain name */
  * Private state.
  */
 
-/* proc_dir_entry for /proc/net/ipconfig */
-static struct proc_dir_entry *ipconfig_dir;
-
 /* Name of user-selected boot device */
 static char user_dev_name[IFNAMSIZ] __initdata = { 0, };
 
@@ -1292,6 +1289,8 @@ static int __init ic_dynamic(void)
 #endif /* IPCONFIG_DYNAMIC */
 
 #ifdef CONFIG_PROC_FS
+/* proc_dir_entry for /proc/net/ipconfig */
+static struct proc_dir_entry *ipconfig_dir;
 
 /* Name servers: */
 static int pnp_seq_show(struct seq_file *seq, void *v)