mac80211: remove IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL

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>
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 07d9957..ab50285 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -502,11 +502,7 @@
 				       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);
 			}
 		}