drm/gud: Replace simple display pipe with DRM atomic helpers

drm/gud: Replace simple display pipe with DRM atomic helpers

The simple display pipe is obsolete and the atomic helpers allow for
more control over the rendering process. As such, this patch replaces
the old simple display pipe system with the newer atomic helpers.

As the code is mainly the same, merely replaced with the new atomic
system, there should be no change in functionality.

Signed-off-by: Ruben Wauters <rubenru09@aol.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250818193553.2162-1-rubenru09@aol.com