ath5k: optimize ath5k_hw_calibration_poll

Optimize ath5k_hw_calibration_poll() since it is called on every singe
interrupt.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index d84ccde..3f56d9e 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -1100,7 +1100,7 @@
 	s32			ah_noise_floor;
 
 	/* Calibration timestamp */
-	unsigned long		ah_cal_tstamp;
+	unsigned long		ah_cal_next_full;
 
 	/* Calibration mask */
 	u8			ah_cal_mask;