wifi: iwlwifi: mvm/mld: use average RSSI for beacons

wifi: iwlwifi: mvm/mld: use average RSSI for beacons

When connected to an AP, the PHY will typically be tuned to
a higher bandwidth than the beacons are transmitted on, as
they are normally only transmitted on 20 MHz. This can mean
that another STA is simultaneously transmitting on another
channel of the higher bandwidth, and apparently this energy
may be taken into account by the PHY, resulting in elevated
energy readings.

To work around this, track the firmware's corrected beacon
energy data and replace the RSSI in beacons by that. The
replacement happens for all beacons received in the context
of the current MAC or link (depending on FW version), in
which case the filters will drop all else. For a scan, which
is only tuning to 20 MHz channels, the MAC/link ID will be
one that isn't found (the AUX ID 4), and no correction will
be done (nor is it needed.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250711183056.324bfe7027ff.I160f947e7aab30e0110a7019ed46186e57c3de14@changeid