mac802154: add ifname change notifier

This patch adds a netdev notifier for interface renaming. We have a name
attribute inside of subif data struct. This is needed to have always the
actual netdev name in sdata name attribute.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>