ath9k: Handle ATH9K_BEACON_RESET_TSF properly

Clearing a local variable is unnecessary.
Get rid of it.

Signed-off-by: Senthil Balasubramanian <senthilkumar@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 0a3de3f..eb40883 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -3422,7 +3422,6 @@
 
 	beacon_period &= ~ATH9K_BEACON_ENA;
 	if (beacon_period & ATH9K_BEACON_RESET_TSF) {
-		beacon_period &= ~ATH9K_BEACON_RESET_TSF;
 		ath9k_hw_reset_tsf(ah);
 	}