arm64: dts: rockchip: add WiFi+BT support on ROCK Pi4 board

Rock Pi 4 has a on board AP6256 WiFi/BT Module. enable wifi and bluetooth
support on Rock Pi 4 board.

Signed-off-by: Akash Gajjar <akash@openedev.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>