drm/sun4i: de2/de3: Remove unsupported VI layer formats

YUV444 and YVU444 are planar formats, but HW format RGB888 is packed.
This means that those two mappings were never correct. Remove them.

Fixes: 60a3dcf9 ("drm/sun4i: Add DE2 definitions for YUV formats")
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200224173901.174016-2-jernej.skrabec@siol.net