minigbm: remove the deprecated exynos backend

BUG=b:199524294
TEST=CQ

Change-Id: I36ccaee6f979cce2c1eb3b66745e5c8332f594c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/3195181
Tested-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Chia-I Wu <olv@google.com>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
Commit-Queue: Yiwei Zhang <zzyiwei@chromium.org>
1 file changed