USB: at76c50x-usb.c: remove err() usage

err() was a very old USB-specific macro that I thought had
gone away.  This patch removes it from being used in the
driver and uses dev_err() instead.

CC: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/at76c50x-usb.c

@@ -1955,7 +1955,7 @@ static int at76_hw_scan(struct ieee80211_hw *hw,
 	ret = at76_set_card_command(priv->udev, CMD_SCAN, &scan, sizeof(scan));
 
 	if (ret < 0) {
-		err("CMD_SCAN failed: %d", ret);
+		wiphy_err(priv->hw->wiphy, "CMD_SCAN failed: %d\n", ret);
 		goto exit;
 	}