drm/sun4i: Add DE2 definitions for YUV formats

This commit expands translation of DRM YUV format to HW specific
information.

It doesn't do any functional changes.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171201060550.10392-25-jernej.skrabec@siol.net