rockchip: Enable HDMI output on rk3399 board w/ HDMI

rockchip: Enable HDMI output on rk3399 board w/ HDMI

Enable config options and console setting to respective
rk3399 board for HDMI output.

Boards supported and tested on this patch are:
- NanoPc T4
- NanoPi M4
- NanoPi Neo4
- ROC-RK3399-PC
- Rock960

Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>