mac802154: rearrange attribute in ieee802154_hw

This patch removes the priv attribute in ieee802154_hw to the right
section which is commented by attributes which needs to be filled by
driver layer.

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