net: ieee802154: Drop duration settings when the core does it already

The core now knows how to set the symbol duration in a few cases, when
drivers correctly advertise the protocols used on each channel. For
these drivers, there is no more need to bother with symbol duration,
lifs and sifs periods so just drop the duplicated code.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220201180629.93410-5-miquel.raynal@bootlin.com


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