mac80211: move TX info into skb->cb

This patch converts mac80211 and all drivers to have transmit
information and status in skb->cb rather than allocating extra
memory for it and copying all the data around. To make it fit,
a union is used where only data that is necessary for all steps
is kept outside of the union.

A number of fixes were done by Ivo, as well as the rt2x00 part
of this patch.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43legacy/dma.h

@@ -195,7 +195,6 @@ struct b43legacy_dmadesc_meta {
 	dma_addr_t dmaaddr;
 	/* ieee80211 TX status. Only used once per 802.11 frag. */
 	bool is_last_fragment;
-	struct ieee80211_tx_status txstat;
 };
 
 struct b43legacy_dmaring;
@@ -297,8 +296,7 @@ void b43legacy_dma_get_tx_stats(struct b43legacy_wldev *dev,
 				struct ieee80211_tx_queue_stats *stats);
 
 int b43legacy_dma_tx(struct b43legacy_wldev *dev,
-		     struct sk_buff *skb,
-		     struct ieee80211_tx_control *ctl);
+		     struct sk_buff *skb);
 void b43legacy_dma_handle_txstatus(struct b43legacy_wldev *dev,
 				   const struct b43legacy_txstatus *status);