Bluetooth: hci_qca: Send VS pre shutdown command.

WCN399x chips are coex chips, it needs a VS pre shutdown
command while turning off the BT. So that chip can inform
BT is OFF to other active clients.

Signed-off-by: Harish Bandi <c-hbandi@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 3c9fd16..0cfa5b8 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -1386,6 +1386,9 @@ static int qca_power_off(struct hci_dev *hdev)
 {
 	struct hci_uart *hu = hci_get_drvdata(hdev);
 
+	/* Perform pre shutdown command */
+	qca_send_pre_shutdown_cmd(hdev);
+
 	qca_power_shutdown(hu);
 	return 0;
 }