ath9k: Fix bug in NF calibration

The number of chainmasks for AR9285 weren't being
setup when running NF calibration.

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.c b/drivers/net/wireless/ath9k/calib.c
index d16f9fe..c6d1de0 100644
--- a/drivers/net/wireless/ath9k/calib.c
+++ b/drivers/net/wireless/ath9k/calib.c
@@ -620,7 +620,9 @@
 	};
 	u8 chainmask;
 
-	if (AR_SREV_9280(ah))
+	if (AR_SREV_9285(ah))
+		chainmask = 0x9;
+	else if (AR_SREV_9280(ah))
 		chainmask = 0x1B;
 	else
 		chainmask = 0x3F;