ath9k: Merge queue draining functions

The TX queue draining routines have confusing names,
rename them approprately and merge ath_drain_txdataq()
with ath_drain_all_txq().

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/beacon.c b/drivers/net/wireless/ath9k/beacon.c
index be1d84a..61d37be 100644
--- a/drivers/net/wireless/ath9k/beacon.c
+++ b/drivers/net/wireless/ath9k/beacon.c
@@ -220,7 +220,7 @@
 		 * acquires txq lock inside.
 		 */
 		if (sc->sc_nvaps > 1) {
-			ath_tx_draintxq(sc, cabq, false);
+			ath_draintxq(sc, cabq, false);
 			DPRINTF(sc, ATH_DBG_BEACON,
 				"flush previous cabq traffic\n");
 		}