ieee802154: hwsim: Save the current filtering level and use it

Save the requested filtering level in the ->set_promiscuous()
helper. The logic is: either we want to enable promiscuous mode and we
want to disable filters entirely, or we want to use the highest
filtering level by default. This is of course an assumption that only
works today, but if in the future intermediate levels (such as scan
filtering level) are implemented in the core, this logic will need to be
updated. This would imply replacing ->set_promiscuous() by something
more fine grained anyway, so we are probably safe with this assumption.

Once saved in the PIB structure, we can use this value instead of trying
to access the PHY structure to know what hardware filtering level has
been advertised.

Suggested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20221019134423.877169-3-miquel.raynal@bootlin.com


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