cfg/mac80211: define TDLS channel switch feature bit

Define some related TDLS protocol constants and advertise channel switch
support in the extended-capabilities IE when the feature bit is defined.

Actually supporting TDLS channel-switching also requires support for
some new nl80211 commands, to be introduced by future patches.

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/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 442369f..ccdeef2 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -4095,6 +4095,8 @@
  * @NL80211_FEATURE_MAC_ON_CREATE: Device supports configuring
  *	the vif's MAC address upon creation.
  *	See 'macaddr' field in the vif_params (cfg80211.h).
+ * @NL80211_FEATURE_TDLS_CHANNEL_SWITCH: Driver supports channel switching when
+ *	operating as a TDLS peer.
  */
 enum nl80211_feature_flags {
 	NL80211_FEATURE_SK_TX_STATUS			= 1 << 0,
@@ -4125,6 +4127,7 @@
 	NL80211_FEATURE_DYNAMIC_SMPS			= 1 << 25,
 	NL80211_FEATURE_SUPPORTS_WMM_ADMISSION		= 1 << 26,
 	NL80211_FEATURE_MAC_ON_CREATE			= 1 << 27,
+	NL80211_FEATURE_TDLS_CHANNEL_SWITCH		= 1 << 28,
 };
 
 /**