mac80211: support disabling EHT mode

Allow userspace to disable EHT mode.
This forces EHT capable interfaces to disable during association.

Signed-off-by: Muna Sinada <quic_msinada@quicinc.com>
Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
Link: https://lore.kernel.org/r/20220323224636.20211-2-quic_alokad@quicinc.com


[remove stray message change]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>