ARM: dts: rockchip: add display nodes for rk322x

Add display_subsystem, hdmi_phy, vop, and hdmi device nodes plus
a few hdmi pinctrl entries to allow for HDMI output.

Signed-off-by: Justin Swartz <justin.swartz@risingedge.co.za>
[added assigned-clock settings for hdmiphy output]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>