Revert "carl9170: prevent speculative execution"

CVE-2017-5753 (revert embargoed)
CVE-2017-5715 (revert embargoed)

This reverts commit 5f922fcb.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/wireless/ath/carl9170/main.c

@@ -1388,7 +1388,6 @@ static int carl9170_op_conf_tx(struct ieee80211_hw *hw,
 
 	mutex_lock(&ar->mutex);
 	if (queue < ar->hw->queues) {
-		gmb();
 		memcpy(&ar->edcf[ar9170_qmap[queue]], param, sizeof(*param));
 		ret = carl9170_set_qos(ar);
 	} else {