gl-renderer: Add support for a few YUV dmabuf formats

Namely the single-planar YUYV, the two-planar NV12, and the
three-planar YUV420, using the shaders already present in Weston.

Signed-off-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

Maniphest Tasks: T13

Differential Revision: https://phabricator.freedesktop.org/D334
1 file changed