Revert "rtnetlink: Do not generate notifications for CHANGEADDR event"

Revert "rtnetlink: Do not generate notifications for CHANGEADDR event"

This reverts commit cd8966e75ed3c6b41a37047a904617bc44fa481f.

The duplicate CHANGEADDR event message is sent regardless of link
status whereas the setlink changes only generate a notification when
the link is up. Not sending a notification when the link is down breaks
dhcpcd which only processes hwaddr changes when the link is down.

Fixes reported regression:
    https://bugzilla.kernel.org/show_bug.cgi?id=196355

Reported-by: Yaroslav Isakov <yaroslav.isakov@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>