Bluetooth: hci_serdev: Introduce hci_uart_unregister_device()

Several drivers have the same (and incorrect) code in their
_remove() handler.

Coalesce this into a shared function.

Signed-off-by: Ian Molton <ian@mnementh.co.uk>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index aea9301..b725ac4 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -354,3 +354,16 @@ int hci_uart_register_device(struct hci_uart *hu,
 	return err;
 }
 EXPORT_SYMBOL_GPL(hci_uart_register_device);
+
+void hci_uart_unregister_device(struct hci_uart *hu)
+{
+	struct hci_dev *hdev = hu->hdev;
+
+	hci_unregister_dev(hdev);
+	hci_free_dev(hdev);
+
+	cancel_work_sync(&hu->write_work);
+
+	hu->proto->close(hu);
+}
+EXPORT_SYMBOL_GPL(hci_uart_unregister_device);