Bluetooth: btusb: Support public address configuration for MediaTek Chip.

The MediaTek chip support vendor specific HCI command(0xfc1a) to
change the public address. Add hdev->set_bdaddr handler for MediaTek
Chip. After doing a power cycle or MediaTek Bluetooth reset, BD_ADDR
will bring back the original one.
Signed-off-by: mark-yw.chen <mark-yw.chen@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -2200,6 +2200,23 @@ struct btmtk_section_map {
 	};
 } __packed;
 
+static int btusb_set_bdaddr_mtk(struct hci_dev *hdev, const bdaddr_t *bdaddr)
+{
+	struct sk_buff *skb;
+	long ret;
+
+	skb = __hci_cmd_sync(hdev, 0xfc1a, sizeof(bdaddr), bdaddr, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		ret = PTR_ERR(skb);
+		bt_dev_err(hdev, "changing Mediatek device address failed (%ld)",
+			   ret);
+		return ret;
+	}
+	kfree_skb(skb);
+
+	return 0;
+}
+
 static void btusb_mtk_wmt_recv(struct urb *urb)
 {
 	struct hci_dev *hdev = urb->context;
@@ -3819,6 +3836,7 @@ static int btusb_probe(struct usb_interface *intf,
 		hdev->shutdown = btusb_mtk_shutdown;
 		hdev->manufacturer = 70;
 		hdev->cmd_timeout = btusb_mtk_cmd_timeout;
+		hdev->set_bdaddr = btusb_set_bdaddr_mtk;
 		set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
 		data->recv_acl = btusb_recv_acl_mtk;
 	}