This commit adds support for HDMI output.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>