mac80211: fix channel type recalculation with HT and non-HT interfaces

When running an AP interface along with the cooked monitor interface created
by hostapd, adding an interface and deleting it again triggers a channel type
recalculation during which the (non-HT) monitor interface takes precedence
over the HT AP interface, thus causing the channel type to be set to non-HT.
Fix this by ensuring that a more wide channel type will not be overwritten
by a less wide channel type.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/chan.c

@@ -77,6 +77,9 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local,
 		switch (tmp->vif.bss_conf.channel_type) {
 		case NL80211_CHAN_NO_HT:
 		case NL80211_CHAN_HT20:
+			if (superchan > tmp->vif.bss_conf.channel_type)
+				break;
+
 			superchan = tmp->vif.bss_conf.channel_type;
 			break;
 		case NL80211_CHAN_HT40PLUS: