wifi: mac80211: batch recalc during STA flush

When we flush stations, we first take them off the list
and then destroy them one by one. If we do the different
mode recalculations while destroying them, we cause the
following scenario:
 - STA 1 has 80 MHz - min chanctx width is now 80 MHz
 - STA 2 has 80 MHz
 - empty STA list
 - destroy STA 2
 - recalc min chanctx width -> results in 20 MHz as
   the STA list is already empty

This is broken, since as far as the driver is concerned
STA 1 still exists at this point, and this causes issues
at least with iwlwifi.

Fix - and also optimize - this by doing the recalc of
min chanctx width (and also P2P PS) only after all the
stations were removed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230604120651.48d262b6b42d.Ia15532657c17535c28ec0c5df263b65f0f80663c@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>