minigbm: remove KMS dependency

minigbm: remove KMS dependency

Adds unneeded complication and extra kernel patches.
Hopefully with Chrome using modifiers we can remove this.

BUG=b:145747132
TEST=compile and run

Change-Id: I557bbd50828d7e39848c315a44a24587c9e2ce3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/1976277
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>