net: mac802154: Create an offloaded transmission error helper

net: mac802154: Create an offloaded transmission error helper

So far there is only a helper for successful transmissions, which led
device drivers to implement their own handling in case of
error. Unfortunately, we really need all the drivers to give the hand
back to the core once they are done in order to be able to build a
proper synchronous API. So let's create a _xmit_error() helper and take
this opportunity to fill the new device-global field storing Tx
statuses.

Suggested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220407100903.1695973-5-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>