ath9k: Decrease minimum NF threshold

The existing value was too conservative, causing
the history buffer not to be updated.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/calib.h b/drivers/net/wireless/ath9k/calib.h
index d2448f0..32589e0 100644
--- a/drivers/net/wireless/ath9k/calib.h
+++ b/drivers/net/wireless/ath9k/calib.h
@@ -27,7 +27,7 @@
 
 #define AR_PHY_CCA_MAX_GOOD_VALUE      		-85
 #define AR_PHY_CCA_MAX_HIGH_VALUE      		-62
-#define AR_PHY_CCA_MIN_BAD_VALUE       		-121
+#define AR_PHY_CCA_MIN_BAD_VALUE       		-140
 #define AR_PHY_CCA_FILTERWINDOW_LENGTH_INIT     3
 #define AR_PHY_CCA_FILTERWINDOW_LENGTH          5