drm: rockchip: introduce rk3066 hdmi

The RK3066 HDMI TX serves as interface between a LCD Controller and
a HDMI bus. A HDMI TX consists of one HDMI transmitter controller and
one HDMI transmitter PHY. The interface has three (3) 8-bit data channels
which can be configured for a number of bus widths (8/10/12/16/20/24-bit)
and different video formats (RGB, YCbCr).

Features:
HDMI version 1.4a, HDCP revision 1.4 and
DVI version 1.0 compliant transmitter.
Supports DTV resolutions from 480i to 1080i/p HD.
Master I2C interface for a DDC connection.
HDMI TX supports multiple power save modes.
The HDMI TX input can switch between LCDC0 and LCDC1.
(Sound support is not included in this patch)

Signed-off-by: Zheng Yang <zhengyang@rock-chips.com>
Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20190330095639.14626-2-jbx6244@gmail.com