Bluetooth: hci_h5: Add support for binding RTL8723BS with device tree

RTL8723BS is often used in ARM boards, so add ability to bind it
using device tree.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Alistair Francis <alistair@alistair23.me>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>