drm/sun4i: sun8i-csc: Secondary CSC register correction

"Allwinner V3s" has secondary video layer (VI).
Decoded video is displayed in wrong colors until
secondary CSC registers are programmed correctly.

Fixes: 88302939

 ("drm/sun4i: Add DE2 CSC library")
Signed-off-by: Martin Cerveny <m.cerveny@computer.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200906162140.5584-2-m.cerveny@computer.org