net: ieee802154: mcr20a: Fix lifs/sifs periods

These periods are expressed in time units (microseconds) while 40 and 12
are the number of symbol durations these periods will last. We need to
multiply them both with phy->symbol_duration in order to get these
values in microseconds.

Fixes: 8c6ad9cc

 ("ieee802154: Add NXP MCR20A IEEE 802.15.4 transceiver driver")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220125121426.848337-3-miquel.raynal@bootlin.com


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