Bluetooth: btusb: Fix not being able to reconnect after suspend

This partially reverts 81b3e33bb054 ("Bluetooth: btusb: Don't fail
external suspend requests") as it introduced a call to hci_suspend_dev
that assumes the system-suspend which doesn't work well when just the
device is being suspended because wakeup flag is only set for remote
devices that can wakeup the system.

Reported-by: Rafael J. Wysocki <[e-mail]>
Reported-by: Heiner Kallweit <[e-mail]>
Reported-by: Kenneth Crudup <[e-mail]>
Fixes: 610712298b11 ("Bluetooth: btusb: Don't fail external suspend requests")
Signed-off-by: Luiz Augusto von Dentz <[e-mail]>
Tested-by: Rafael J. Wysocki <[e-mail]>

drivers/bluetooth/btusb.c

···
 static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct btusb_data *data = usb_get_intfdata(intf);
-	int err;
 
 	BT_DBG("intf %p", intf);
 
···
 	if (data->suspend_count++)
 		return 0;
 
-	/* Notify Host stack to suspend; this has to be done before stopping
-	 * the traffic since the hci_suspend_dev itself may generate some
-	 * traffic.
-	 */
-	err = hci_suspend_dev(data->hdev);
-	if (err) {
-		data->suspend_count--;
-		return err;
-	}
-
 	spin_lock_irq(&data->txlock);
 	if (!(PMSG_IS_AUTO(message) && data->tx_in_flight)) {
 		set_bit(BTUSB_SUSPENDING, &data->flags);
···
 	} else {
 		spin_unlock_irq(&data->txlock);
 		data->suspend_count--;
-		hci_resume_dev(data->hdev);
 		return -EBUSY;
 	}
 
···
 	clear_bit(BTUSB_SUSPENDING, &data->flags);
 	spin_unlock_irq(&data->txlock);
 	schedule_work(&data->work);
-
-	hci_resume_dev(data->hdev);
 
 	return 0;