neigh: ipv6: respect default values set before an address is assigned to device

Make the behaviour similar to ipv4. This will allow user to set sysctl
default neigh param values and these values will be respected even by
devices registered before (that ones what do not have address set yet).

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index e70278e..66c4a44 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -248,6 +248,13 @@
 	return idev;
 }
 
+static inline struct neigh_parms *__in6_dev_nd_parms_get_rcu(const struct net_device *dev)
+{
+	struct inet6_dev *idev = __in6_dev_get(dev);
+
+	return idev ? idev->nd_parms : NULL;
+}
+
 void in6_dev_finish_destroy(struct inet6_dev *idev);
 
 static inline void in6_dev_put(struct inet6_dev *idev)