mac80211: fix TX sequence numbers

This patch makes mac80211 assign proper sequence numbers to
QoS-data frames. It also removes the old sequence number code
because we noticed that only the driver or hardware can assign
sequence numbers to non-QoS-data and especially management
frames in a race-free manner because beacons aren't passed
through mac80211's TX path.

This patch also adds temporary code to the rt2x00 drivers to
not break them completely, that code will have to be reworked
for proper sequence numbers on beacons.

It also moves sequence number assignment down in the TX path
so no sequence numbers are assigned to frames that are dropped.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/sta_info.h

@@ -285,6 +285,7 @@ struct sta_info {
 	unsigned long tx_fragments;
 	int txrate_idx;
 	int last_txrate_idx;
+	u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
 #ifdef CONFIG_MAC80211_DEBUG_COUNTERS
 	unsigned int wme_tx_queue[NUM_RX_DATA_QUEUES];
 #endif