wifi: mac80211: Allow NSS change only up to capability

Stations can update bandwidth/NSS change in
VHT action frame with action type Operating Mode Notification.
(IEEE Std 802.11-2020 - 9.4.1.53 Operating Mode field)

For Operating Mode Notification, an RX NSS change to a value
greater than AP's maximum NSS should not be allowed.
During fuzz testing, by forcefully sending VHT Op. mode notif.
frames from STA with random rx_nss values, it is found that AP
accepts rx_nss values greater that APs maximum NSS instead of
discarding such NSS change.

Hence allow NSS change only up to maximum NSS that is negotiated
and capped to AP's capability during association.

Signed-off-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Link: https://lore.kernel.org/r/20230207114146.10567-1-quic_ramess@quicinc.com


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