wifi: mac80211: add a per-PHY AQL limit to improve fairness

wifi: mac80211: add a per-PHY AQL limit to improve fairness

In order to maintain fairness, the amount of queueing needs to be limited
beyond the simple per-station AQL budget, otherwise the driver can simply
repeatedly do scheduling rounds until all queues that have not used their
AQL budget become eligble.

To be conservative, use the high AQL limit for the first txq and add half
of the low AQL for each subsequent queue.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://lore.kernel.org/r/20220625212411.36675-5-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>