carl9170: add missing return-value check

This patch adds a forgotten bail-out path.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
index 82bc81c..122e75e 100644
--- a/drivers/net/wireless/ath/carl9170/phy.c
+++ b/drivers/net/wireless/ath/carl9170/phy.c
@@ -1676,6 +1676,8 @@
 
 	err = carl9170_write_reg(ar, AR9170_PHY_REG_HEAVY_CLIP_ENABLE,
 				 0x200);
+	if (err)
+		return err;
 
 	err = carl9170_init_rf_bank4_pwr(ar,
 		channel->band == IEEE80211_BAND_5GHZ,