As I said in patch 'rtnetlink: bring NETDEV_CHANGEMTU event process back
in rtnetlink_event', removing NETDEV_POST_TYPE_CHANGE event was not the
right fix for the redundant notifications issue.

So bring this event process back to rtnetlink_event and the old redundant
notifications issue would be fixed in the later patch 'rtnetlink: check
DO_SETLINK_NOTIFY correctly in do_setlink'.

Fixes: aef091ae ("rtnetlink: Do not generate notifications for POST_TYPE_CHANGE event")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>