mac80211: disable 80+80/160 in VHT correctly

The supported bandwidth field is a two-bit field, not a bitmap,
so treat it accordingly when disabling 80+80 or 160 MHz.

Note that we can only advertise "80+80 and 160" or "160", not
"80+80" by itself, so disabling 160 also disables 80+80.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -552,13 +552,17 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
 	cap = vht_cap.cap;
 
 	if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_80P80MHZ) {
-		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
-		cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+		u32 bw = cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
+
+		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
+		if (bw == IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ ||
+		    bw == IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)
+			cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
 	}
 
 	if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_160MHZ) {
 		cap &= ~IEEE80211_VHT_CAP_SHORT_GI_160;
-		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
 	}
 
 	/*