IPV6: /proc/net/anycast6 unbalanced inet6_dev refcnt

Reading /proc/net/anycast6 when there is no anycast address
on an interface results in an ever-increasing inet6_dev reference
count, as well as a reference to the netdevice you can't get rid of.
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Marcus Meissner <meissner@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/ipv6/anycast.c

@@ -66,6 +66,7 @@ ip6_onlink(struct in6_addr *addr, struct net_device *dev)
 				break;
 		}
 		read_unlock_bh(&idev->lock);
+		in6_dev_put(idev);
 	}
 	rcu_read_unlock();
 	return onlink;