mac80211: disable HT advertising unless AP supports it

If the AP doesn't support HT, or more importantly if
it does but we have to disable it because its IEs are
broken, don't advertise HT support in our association
request. Otherwise, we configure our channel to be a
20 MHz non-HT channel but the AP might still think we
support HT, or even 40 MHz.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -3267,6 +3267,7 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 		sdata->needed_rx_chains = min(chains, local->rx_chains);
 	} else {
 		sdata->needed_rx_chains = 1;
+		sdata->u.mgd.flags |= IEEE80211_STA_DISABLE_HT;
 	}
 
 	/* will change later if needed */