cfg80211/mac80211: Use more generic bitrate mask for rate control

Extend struct cfg80211_bitrate_mask to actually use a bitfield mask
instead of just a single fixed or maximum rate index. This change
itself does not modify the behavior (except for debugfs files), but it
prepares cfg80211 and mac80211 for a new nl80211 command for setting
which rates can be used in TX rate control.

Since frames are now going through the rate control algorithm
unconditionally, the internal IEEE80211_TX_INTFL_RCALGO flag can now
be removed. The RC implementations can use the rate_idx_mask value to
optimize their behavior if only a single rate is enabled.

The old max_rate_idx in struct ieee80211_tx_rate_control is maintained
(but commented as deprecated) for backwards compatibility with existing
RC implementations. Once these implementations have been updated to
use the more generic rate_idx_mask, the max_rate_idx value can be
removed.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rate.h b/net/mac80211/rate.h
index cb9bd1f..669dddd 100644
--- a/net/mac80211/rate.h
+++ b/net/mac80211/rate.h
@@ -44,10 +44,7 @@
 	struct rate_control_ref *ref = local->rate_ctrl;
 	struct ieee80211_sta *ista = &sta->sta;
 	void *priv_sta = sta->rate_ctrl_priv;
-	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-
-	if (likely(info->flags & IEEE80211_TX_INTFL_RCALGO))
-		ref->ops->tx_status(ref->priv, sband, ista, priv_sta, skb);
+	ref->ops->tx_status(ref->priv, sband, ista, priv_sta, skb);
 }