The current filtering level is set on the first interface up on a wpan
phy. If we support scan functionality we need to change the filtering
level on the fly on an operational phy and switching back again.

This patch will move the receive mode parameter e.g. address filter and
promiscuous mode to the drv_start() functionality to allow changing the
receive mode on an operational phy not on first ifup only. In future this
should be handled on driver layer because each hardware has it's own way
to enter a specific filtering level. However this should offer to switch
to mode IEEE802154_FILTERING_NONE and back to
IEEE802154_FILTERING_4_FRAME_FIELDS.

Only IEEE802154_FILTERING_4_FRAME_FIELDS and IEEE802154_FILTERING_NONE
are somewhat supported by current hardware. All other filtering levels
can be supported in future but will end in IEEE802154_FILTERING_NONE as
the receive part can kind of "emulate" those receive paths by doing
additional filtering routines.

There are in total three filtering levels in the code:
- the per-interface default level (should not be changed)
- the required per-interface level (mac commands may play with it)
- the actual per-PHY (hw) level that is currently in use
Signed-off-by: Alexander Aring <aahringo@redhat.com>
[<miquel.raynal@bootlin.com: Add the third filtering variable]
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20221007085310.503366-4-miquel.raynal@bootlin.comSigned-off-by: Stefan Schmidt <stefan@datenfreihafen.org>