ath9k: Fix code mistake

The commit "ath9k: Process GTT interrupts" accidentally
had a line that was commented out.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/main.c

@@ -524,7 +524,7 @@ void ath9k_tasklet(unsigned long data)
 			 * successfully after a GTT interrupt, the GTT counter
 			 * gets reset to zero here.
 			 */
-			/* sc->gtt_cnt = 0; */
+			sc->gtt_cnt = 0;
 
 			ath_tx_edma_tasklet(sc);
 		} else {