mac80211: Handle SMPS mode changes only in AP mode

mac80211: Handle SMPS mode changes only in AP mode

According to IEEE802.11 specifications the SM power save field
in the HT capability IE and the HE extended capability IE is valid
only in (re)association frames and should be ignored otherwise.
Remove code paths that handled this also for non AP modes.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20200131111300.891737-17-luca@coelho.fi
Signed-off-by: Johannes Berg <johannes.berg@intel.com>