This is basically a revert of:
commit 
5b632fe85ec82e5c43740b52e74c66df50a37db3
Author: Stanislaw Gruszka <sgruszka@redhat.com>
Date:   Mon Dec 3 12:56:33 2012 +0100
    mac80211: introduce IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL
We do not need this flag any longer, rt2x00 BAR/BA problem was fixed
correctly by wireless-testing commit:
commit 
84e9e8ebd369679a958200a8baca96aafb2393bb
Author: Helmut Schaa <helmut.schaa@googlemail.com>
Date:   Thu Jan 17 17:34:32 2013 +0100
    rt2x00: Improve TX status handling for BlockAckReq frames
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
  * @IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF: Use the P2P Device address for any
  *     P2P Interface. This will be honoured even if more than one interface
  *     is supported.
- *
- * @IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL: On this hardware TX BA session
- *     should be tear down once BAR frame will not be acked.
- *
  */
 enum ieee80211_hw_flags {
        IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
        IEEE80211_HW_TX_AMPDU_SETUP_IN_HW               = 1<<23,
        IEEE80211_HW_SCAN_WHILE_IDLE                    = 1<<24,
        IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF              = 1<<25,
-       IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL          = 1<<26,
 };
 
 /**
 
                                       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
                                      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;
 
-                               if (local->hw.flags &
-                                   IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL)
-                                       ieee80211_stop_tx_ba_session(&sta->sta, tid);
-                               else
-                                       ieee80211_set_bar_pending(sta, tid, ssn);
+                               ieee80211_set_bar_pending(sta, tid, ssn);
                        }
                }