net: ieee802154: Enhance/fix the names of the MLME return codes

Let's keep these definitions as close to the specification as possible
while they are not yet in use. The names get slightly longer, but we
gain the minor cost of being able to search the spec more easily.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220407100903.1695973-2-miquel.raynal@bootlin.com


Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>