ath9k: properly use the mac80211 rate control api

This patch changes ath9k to pass proper MCS indexes and flags
between the RC and the rest of the driver code.
sc->cur_rate_table remains, as it's used by the RC code internally,
but the rest of the driver code no longer uses it, so a potential
new RC for ath9k would not have to update it.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/rc.h b/drivers/net/wireless/ath/ath9k/rc.h
index 51f85ec..d68bc94 100644
--- a/drivers/net/wireless/ath/ath9k/rc.h
+++ b/drivers/net/wireless/ath/ath9k/rc.h
@@ -104,6 +104,7 @@
  */
 struct ath_rate_table {
 	int rate_cnt;
+	int mcs_start;
 	struct {
 		int valid;
 		int valid_single_stream;
@@ -179,8 +180,6 @@
 	ATH9K_INT_UNPAUSE
 };
 
-void ath_rate_attach(struct ath_softc *sc);
-u8 ath_rate_findrateix(struct ath_softc *sc, u8 dot11_rate);
 int ath_rate_control_register(void);
 void ath_rate_control_unregister(void);