net: mac802154: Avoid displaying misleading debug information

net: mac802154: Avoid displaying misleading debug information

With DEBUG defined, any frame received will see its MHR fields (fc and
addresses, mainly) being printed in the kernel log buffer,
unconditionally. In most cases this is fine, but in some specific cases
(like Acknowledgment frames, where both the source and destination
addressing fields are omitted), it displays garbage which is
misleading.

Only print the addressing fields when they are present, which clarifies
the logs.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220905202724.1322046-1-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>