mac80211: restructure HT code

Create two new files, agg-tx.c and agg-rx.c to make it clearer
which code is common (ht.c) and which is specific (agg-*.c).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 5b23001..6987dfa 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -987,6 +987,9 @@
 			struct ieee80211_ht_info *hti,
 			u16 ap_ht_cap_flags);
 void ieee80211_send_bar(struct ieee80211_sub_if_data *sdata, u8 *ra, u16 tid, u16 ssn);
+void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
+			  const u8 *da, u16 tid,
+			  u16 initiator, u16 reason_code);
 
 void ieee80211_sta_stop_rx_ba_session(struct ieee80211_sub_if_data *sdata, u8 *da,
 				u16 tid, u16 initiator, u16 reason);