minigbm: komeda: Refactor the 'dumb' drivers and add Komeda support

minigbm: komeda: Refactor the 'dumb' drivers and add Komeda support

Several drivers are very similar in that they only use the 'dumb'
operations. This patch puts all such drivers into a single file and
also adds a driver to support the Arm Komeda/D71 display processor.

TEST=Boot Android and verify that we reach the home screen

Change-Id: If39605deaef446adf8d6693d760a16c2c3f84649
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/2429952
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Gurchetan Singh <gurchetansingh@chromium.org>