ath9k: Maintain rate table choice after association

A scan run after association would change sc_curmode which is
used to get the current rate table. This patch fixes it
by removing sc_curmode and setting the rate table in usage in cur_rate_table
on association.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c
index 7a45546..b182ef5 100644
--- a/drivers/net/wireless/ath9k/recv.c
+++ b/drivers/net/wireless/ath9k/recv.c
@@ -148,7 +148,7 @@
 			  struct ieee80211_rx_status *rx_status, bool *decrypt_error,
 			  struct ath_softc *sc)
 {
-	struct ath_rate_table *rate_table = sc->hw_rate_table[sc->sc_curmode];
+	struct ath_rate_table *rate_table = sc->cur_rate_table;
 	struct ieee80211_hdr *hdr;
 	int ratekbps, rix;
 	u8 ratecode;