ath9k_hw: fix calibration on 5 ghz

ADC calibrations cannot run on 5 GHz with fast clock enabled. They
need to be disabled, otherwise they'll hang and IQ mismatch calibration
will not be run either.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Reported-by: Adrian Chadd <adrian@freebsd.org>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ar9002_calib.c

@@ -41,7 +41,8 @@ static bool ar9002_hw_is_cal_supported(struct ath_hw *ah,
 	case ADC_DC_CAL:
 		/* Run ADC Gain Cal for non-CCK & non 2GHz-HT20 only */
 		if (!IS_CHAN_B(chan) &&
-		    !(IS_CHAN_2GHZ(chan) && IS_CHAN_HT20(chan)))
+		    !((IS_CHAN_2GHZ(chan) || IS_CHAN_A_FAST_CLOCK(ah, chan)) &&
+		      IS_CHAN_HT20(chan)))
 			supported = true;
 		break;
 	}