mac80211: track AP and peer STA TDLS chan-switch support

The AP or peer can prohibit TDLS channel switch via a bit in the
extended capabilities IE. Parse the IE and track this bit. Set an
appropriate STA flag if both the AP and peer STA support TDLS
channel-switching.

Add the new STA flag and the missing TDLS_INITIATOR to debugfs.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 11a937f..45490a2 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2802,6 +2802,9 @@
 	}
 
 	ifmgd->aid = aid;
+	ifmgd->tdls_chan_switch_prohibited =
+		elems.ext_capab && elems.ext_capab_len >= 5 &&
+		(elems.ext_capab[4] & WLAN_EXT_CAPA5_TDLS_CH_SW_PROHIBITED);
 
 	/*
 	 * Some APs are erroneously not including some information in their