wifi: mac80211: hide element parsing internals

Rework the data structures to hide element parsing internals
from the users.

Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240228094902.19c610b529e2.Ie7ea2dcb6713911590ace6583a4748f32dc37df2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

wifi: mac80211: clean up connection process

Rewrite the station-side connection handling. The connection
flags (IEEE80211_DISABLE_*) are rather confusing, and they're
not always maintained well. Additionally, for wider-bandwidth
OFDMA support we need to know the precise bandwidth of the AP,
which is currently somewhat difficult.

Rewrite this to have a 'mode' (S1G/legacy/HT/...) and a limit
on the bandwidth. This is not entirely clean because some of
those modes aren't completely sequenced (as this assumes in
some places), e.g. VHT doesn't exist on 2.4 GHz, but HE does.
However, it still simplifies things and gives us a good idea
what we're operating as, so we can parse elements accordingly
etc.

This leaves a FIXME for puncturing, this is addressed in a
later patch.

Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240129194108.9451722c0110.I3e61f4cfe9da89008e1854160093c76a1e69dc2a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

wifi: mac80211: add an element parsing unit test

Add a unit test for the parsing of a fragmented sta profile
sub-element inside a fragmented multi-link element.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230827135854.333bc75df13f.I0ddfeb6a88a4d89e7c7850e8ef45a4b19b5a061a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>