iwlwifi: mvm: correctly set the flags for BAR

Somehow, the Tx flags for BAR were completely wrong.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/mvm/tx.c

@@ -180,7 +180,8 @@ static void iwl_mvm_set_tx_cmd_rate(struct iwl_mvm *mvm,
 		tx_cmd->tx_flags |= cpu_to_le32(TX_CMD_FLG_STA_RATE);
 		return;
 	} else if (ieee80211_is_back_req(fc)) {
-		tx_cmd->tx_flags |= cpu_to_le32(TX_CMD_FLG_STA_RATE);
+		tx_cmd->tx_flags |=
+			cpu_to_le32(TX_CMD_FLG_ACK | TX_CMD_FLG_BAR);
 	}
 
 	/* HT rate doesn't make sense for a non data frame */