minigbm: dri,amdgpu: Modifier support.

minigbm: dri,amdgpu: Modifier support.

This adds modifier support to minigbm in the amdgpu driver.

This includes

(a) creation of images with modifiers
(b) imports
  - Had to distinguish between legacy and non-legacy.
(c) Support for planes > format planes

BUG=b:149819940
TEST=Login on a Zork device + play a YT video.

Change-Id: If58ada081aa254932e299536c48c18937266c2e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/2093212
Tested-by: Bas Nieuwenhuizen <basni@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Bas Nieuwenhuizen <basni@chromium.org>