ath9k: fix compile error in non-debug ath_debug_stat_tx() stub

"ath9k: fix tx queue index confusion in debugfs code" changed the debug
function but not the stub.

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/debug.h b/drivers/net/wireless/ath/ath9k/debug.h
index 1bdc6d4..59338de 100644
--- a/drivers/net/wireless/ath/ath9k/debug.h
+++ b/drivers/net/wireless/ath/ath9k/debug.h
@@ -192,7 +192,8 @@
 
 static inline void ath_debug_stat_tx(struct ath_softc *sc,
 				     struct ath_buf *bf,
-				     struct ath_tx_status *ts)
+				     struct ath_tx_status *ts,
+				     struct ath_txq *txq)
 {
 }