ath9k_hw: fix a small typo in the noisefloor calibration debug code

In the noisefloor array, the extension channel values start at index 3
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -278,7 +278,7 @@ static void ath9k_hw_nf_sanitize(struct ath_hw *ah, s16 *nf)
 
 		ath_print(common, ATH_DBG_CALIBRATE,
 			  "NF calibrated [%s] [chain %d] is %d\n",
-			  (i > 3 ? "ext" : "ctl"), i % 3, nf[i]);
+			  (i >= 3 ? "ext" : "ctl"), i % 3, nf[i]);
 
 		if (nf[i] > limit->max) {
 			ath_print(common, ATH_DBG_CALIBRATE,