ieee802154: atusb: add support for trac feature

ieee802154: atusb: add support for trac feature

This patch adds support for reading the trac register if atusb firmware
reports tx done. There is currently a feature to compare a sequence
number, if the payload is 1 it tells the driver only the sequence number
is available if it's two there is additional the trac status register as
payload.

Currently the atusb_in_good() function determines if it's a tx done or
rx done if according the payload length. This patch is doing the same
and assumes this behaviour.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220905203412.1322947-10-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>