Tell user why a channel cannot be used in AP mode

Signed-off-by: Ben Greear <greearb@candelatech.com>

src/ap/hw_features.c

@@ -631,8 +631,15 @@ int hostapd_select_hw_mode(struct hostapd_iface *iface)
 			if (chan->flag & HOSTAPD_CHAN_DISABLED) {
 				wpa_printf(MSG_ERROR,
 					   "channel [%i] (%i) is disabled for "
-					   "use in AP mode, flags: 0x%x",
-					   j, chan->chan, chan->flag);
+					   "use in AP mode, flags: 0x%x%s%s%s",
+					   j, chan->chan, chan->flag,
+					   chan->flag & HOSTAPD_CHAN_NO_IBSS ?
+					   " NO-IBSS" : "",
+					   chan->flag &
+					   HOSTAPD_CHAN_PASSIVE_SCAN ?
+					   " PASSIVE-SCAN" : "",
+					   chan->flag & HOSTAPD_CHAN_RADAR ?
+					   " RADAR" : "");
 			} else {
 				ok = 1;
 				break;