Bluetooth: Add shutdown callback before closing the device

This callback allows a vendor to send the vendor specific commands
before cloing the hci interface.

Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 3322d3f..4135a440 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1591,6 +1591,12 @@
 {
 	BT_DBG("%s %p", hdev->name, hdev);
 
+	if (!test_bit(HCI_UNREGISTER, &hdev->dev_flags)) {
+		/* Execute vendor specific shutdown routine */
+		if (hdev->shutdown)
+			hdev->shutdown(hdev);
+	}
+
 	cancel_delayed_work(&hdev->power_off);
 
 	hci_req_cancel(hdev, ENODEV);