wifi: mac80211: Refactor adding association elements

wifi: mac80211: Refactor adding association elements

Instead of always using 'sdata->u.mgd.assoc_data' have
the association data be passed as an argument.

This will later allow to use the same functionality
for adding links to the current association.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250102161730.191f58f2bba7.I6baa6e2989a39937234ff91d7db5ff1359a6bb30@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>