ath5k: IQ calibration for AR5211 is slightly different

according to the HAL sources the calculation of the Q value is slightly
different for AR5211 chips.

i couldn't test this since IQ calibration never finishes on older parts. this
is a different problem...
Signed-off-by: NBruno Randolf <br1@einfach.org>
Acked-by: NNick Kossifidis <mickflemm@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/phy.c

@@ -1391,7 +1391,11 @@ static int ath5k_hw_rf511x_calibrate(struct ath5k_hw *ah,
 	}
 
 	i_coffd = ((i_pwr >> 1) + (q_pwr >> 1)) >> 7;
-	q_coffd = q_pwr >> 7;
+
+	if (ah->ah_version == AR5K_AR5211)
+		q_coffd = q_pwr >> 6;
+	else
+		q_coffd = q_pwr >> 7;
 
 	/* No correction */
 	if (i_coffd == 0 || q_coffd == 0)
@@ -1405,7 +1409,10 @@ static int ath5k_hw_rf511x_calibrate(struct ath5k_hw *ah,
 	if (i_coff < -32)
 		i_coff = -32;
 
-	q_coff = (((s32)i_pwr / q_coffd) - 128);
+	if (ah->ah_version == AR5K_AR5211)
+		q_coff = (i_pwr / q_coffd) - 64;
+	else
+		q_coff = (i_pwr / q_coffd) - 128;
 
 	/* Boundary check */
 	if (q_coff > 15)