Do not disable 40 MHz based on co-ex report with matching primary channel

When processing 20/40 BSS Coexistence Management frames that do not
explicitly require 40 MHz to be disabled, check whether the reported
channels in 20/40 BSS Intolerant Channel Report element match the
current primary channel. If so, allow 40 MHz operation to continue. This
makes the during-operation updates for 20/40 Operation Permitted more
consistent with the scans during initial BSS startup.

The received 20/40 BSS Intolerant Channel Report channels are to be used
in the OT set in the during-operation determination and the P == OT_i
exception was ignored in the previous implementation which could result
in the AP first starting with 40 MHz and then dropping to 20 MHz on
first received 20/40 BSS Coexistence Management frame even though there
was no change in the neighboring BSSs.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

src/ap/ieee802_11_ht.c

@@ -332,8 +332,10 @@ void hostapd_2040_coex_action(struct hostapd_data *hapd,
 		for (i = 0; i < ielen - 1; i++) {
 			u8 chan = ic_report->variable[i];
 
+			if (chan == iface->conf->channel)
+				continue; /* matching own primary channel */
 			if (is_40_allowed(iface, chan))
-				continue;
+				continue; /* not within affected channels */
 			hostapd_logger(hapd, mgmt->sa,
 				       HOSTAPD_MODULE_IEEE80211,
 				       HOSTAPD_LEVEL_DEBUG,