rtnetlink: ignore NETDEV_PRE_UP notifier in rtnetlink_event()

Commit 3b8bcfd5 (net: introduce pre-up netdev notifier) added a new
notifier which is run before a device is set UP for use by cfg80211.

The patch missed to add the new notifier to the ignore list in
rtnetlink_event(), so we currently get an unnecessary netlink
notification before a device is set UP.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>