[IPV4]: Make __devinet_sysctl_register return an error

Currently, this function is void, so failures in creating
sysctls for new/renamed devices are not reported to anywhere.

Fixing this is another complex (needed?) task, but this
return value is needed during the namespaces creation to
handle the case, when we failed to create "all" and "default"
entries.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/devinet.c

@@ -1454,8 +1454,8 @@ static struct devinet_sysctl_table {
 	},
 };
 
-static void __devinet_sysctl_register(char *dev_name, int ctl_name,
-		struct ipv4_devconf *p)
+static int __devinet_sysctl_register(struct net *net, char *dev_name,
+		int ctl_name, struct ipv4_devconf *p)
 {
 	int i;
 	struct devinet_sysctl_table *t;
@@ -1497,14 +1497,14 @@ static void __devinet_sysctl_register(char *dev_name, int ctl_name,
 		goto free_procname;
 
 	p->sysctl = t;
-	return;
+	return 0;
 
 free_procname:
 	kfree(t->dev_name);
 free:
 	kfree(t);
 out:
-	return;
+	return -ENOBUFS;
 }
 
 static void __devinet_sysctl_unregister(struct ipv4_devconf *cnf)