ARM: dts: rockchip: Add io-domain node for rk3228

This patch adds io-domain support for rk3228 SoC.

Signed-off-by: David Wu <david.wu@rock-chips.com>
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>