This adds video output support for Amlogic GXBB/GXL/GXM chips.
The supported ports are CVBS and HDMI (based on DW_HDMI).

When using HDMI, only DMT modes are supported.

There is support for simple-framebuffer (CONFIG_VIDEO_DT_SIMPLEFB)
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NJorge Ramire-Ortiz <jramirez@baylibre.com>
Signed-off-by: NMaxime Jourdan <mjourdan@baylibre.com>
[narmstrong: fixed defines alignment in meson_canvas.c]
Reviewed-by: NAnatolij Gustschin <agust@denx.de>