arm64: dts: rockchip: add RK3328 eavluation board devicetree

This patch add rk3328-evb.dts for RK3328 evaluation board.
Tested on RK3328 evb.

Signed-off-by: Liang Chen <cl@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>