wifi: mac80211: use bandwidth indication element for CSA

In CSA, parse the (EHT) bandwidth indication element and
use it (in fact prefer it if present).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230920211508.43ef01920556.If4f24a61cd634ab1e50eba43899b9e992bf25602@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>