[PATCH] ipv6: fix inet6_dev refcnt with IPV6_PRIVACY enabled

When IPV6_PRIVACY is enabled, in ipv6_add_dev we have second extra 
in6_dev_hold while preparing to call ipv6_regen_rndid, and only 
one in6_dev_put call in addrconf_ifdown for inet6_dev devices with 
active regen_timer.

That leaves inet6_dev with refcnt equals to 1 and blocks device unregistration:
"unregister_netdevice: waiting for usb0 to become free. Usage count = 1"

Signed-off-by: Sergey Senozhatsky <redacted>

---

 net/ipv6/addrconf.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2fc35b3..541f773 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c

@@ -425,7 +425,6 @@ static struct inet6_dev * ipv6_add_dev(struct net_device *dev)
 		       dev->name);
 		ndev->cnf.use_tempaddr = -1;
 	} else {
-		in6_dev_hold(ndev);
 		ipv6_regen_rndid((unsigned long) ndev);
 	}
 #endif