Fix channel switch to disable VHT with HT

If both HT and VHT was enabled on AP and channel switch event from the
driver indicated that HT was disabled, VHT was left enabled. This
resulted in the following channel configuration failing. Fix this by
disabling VHT if HT gets disabled.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/ap/drv_callbacks.c

@@ -489,6 +489,8 @@ void hostapd_event_ch_switch(struct hostapd_data *hapd, int freq, int ht,
 
 	hapd->iconf->channel = channel;
 	hapd->iconf->ieee80211n = ht;
+	if (!ht)
+		hapd->iconf->ieee80211ac = 0;
 	hapd->iconf->secondary_channel = offset;
 	hapd->iconf->vht_oper_chwidth = chwidth;
 	hapd->iconf->vht_oper_centr_freq_seg0_idx = seg0_idx;