mac80211: allow drivers to request SMPS off

Previously we were warning and using automatic when a driver sent an
update request with SMPS off.  This patch makes it possible for
drivers to disable SMPS at runtime, for whatever reason.
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ht.c

@@ -482,8 +482,6 @@ void ieee80211_request_smps(struct ieee80211_vif *vif,
 		return;
 
 	if (vif->type == NL80211_IFTYPE_STATION) {
-		if (WARN_ON(smps_mode == IEEE80211_SMPS_OFF))
-			smps_mode = IEEE80211_SMPS_AUTOMATIC;
 		if (sdata->u.mgd.driver_smps_mode == smps_mode)
 			return;
 		sdata->u.mgd.driver_smps_mode = smps_mode;