mac80211: enable TDLS peer buffer STA feature

Allow drivers to set the buffer station extended capability
for TDLS links, with a new hardware flag indicating this.

Signed-off-by: Yingying Tang <yintang@qti.qualcomm.com>
[change commit log/documentation wording]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index eec143c..2ee4af2 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2056,6 +2056,9 @@ struct ieee80211_txq {
  *	The stack will not do fragmentation.
  *	The callback for @set_frag_threshold should be set as well.
  *
+ * @IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA: Hardware supports buffer STA on
+ *	TDLS links.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2098,6 +2101,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_TX_FRAG_LIST,
 	IEEE80211_HW_REPORTS_LOW_ACK,
 	IEEE80211_HW_SUPPORTS_TX_FRAG,
+	IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS