atomictest: allow buffers to be created with modifiers

Option to specify which modifier to use when
creating buffers to display.

BUG=b:148693192
TEST=atomictest -t crtc_ctm -m DRM_FORMAT_MOD_LINEAR

Change-Id: Id2612d6319e87ccce2fbf8973aad5e0e53cabd3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/drm-tests/+/2144945
Tested-by: Fritz Koenig <frkoenig@chromium.org>
Auto-Submit: Fritz Koenig <frkoenig@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Fritz Koenig <frkoenig@chromium.org>
1 file changed