mac80211: dont allow fragmentation and requeuing on A-MPDU queues

There really is no reason for a driver to reject a frame on
an A-MPDU queue when it can stop that queue for any period
of time and is given frames one by one. Hence, disallow it
with a big warning and reduce mac80211-internal state.

Also add a warning when we try to fragment a frame destined
for an A-MPDU queue and drop it, the actual bug needs to be
fixed elsewhere but I'm not exactly sure how to yet.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_i.h

@@ -595,7 +595,7 @@ struct ieee80211_local {
 	struct timer_list sta_cleanup;
 
 	unsigned long state[IEEE80211_MAX_QUEUES + IEEE80211_MAX_AMPDU_QUEUES];
-	struct ieee80211_tx_stored_packet pending_packet[IEEE80211_MAX_QUEUES + IEEE80211_MAX_AMPDU_QUEUES];
+	struct ieee80211_tx_stored_packet pending_packet[IEEE80211_MAX_QUEUES];
 	struct tasklet_struct tx_pending_tasklet;
 
 	/* number of interfaces with corresponding IFF_ flags */