net: fix a build failure when !CONFIG_PROC_FS

When !CONFIG_PROC_FS dev_mcast_init() is not defined,
actually we can just merge dev_mcast_init() into
dev_proc_init().
Reported-by: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -2646,7 +2646,6 @@ extern void		netdev_notify_peers(struct net_device *dev);
 extern void		netdev_features_change(struct net_device *dev);
 /* Load a device via the kmod */
 extern void		dev_load(struct net *net, const char *name);
-extern void		dev_mcast_init(void);
 extern struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 					       struct rtnl_link_stats64 *storage);
 extern void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,

net/core/dev.c

@@ -6260,7 +6260,6 @@ static int __init net_dev_init(void)
 
 	hotcpu_notifier(dev_cpu_callback, 0);
 	dst_init();
-	dev_mcast_init();
 	rc = 0;
 out:
 	return rc;

net/core/net-procfs.c

@@ -341,11 +341,6 @@ static struct pernet_operations __net_initdata dev_proc_ops = {
 	.exit = dev_proc_net_exit,
 };
 
-int __init dev_proc_init(void)
-{
-	return register_pernet_subsys(&dev_proc_ops);
-}
-
 static int dev_mc_seq_show(struct seq_file *seq, void *v)
 {
 	struct netdev_hw_addr *ha;
@@ -408,7 +403,10 @@ static struct pernet_operations __net_initdata dev_mc_net_ops = {
 	.exit = dev_mc_net_exit,
 };
 
-void __init dev_mcast_init(void)
+int __init dev_proc_init(void)
 {
-	register_pernet_subsys(&dev_mc_net_ops);
+	int ret = register_pernet_subsys(&dev_proc_ops);
+	if (!ret)
+		return register_pernet_subsys(&dev_mc_net_ops);
+	return ret;
 }