minigbm: close bo handle in bo destroy

minigbm: close bo handle in bo destroy

In dri path the bo handle is not closed in bo destroy. This was
resulting in memory leak. Closed the bo handle in bo destroy.

BUG=b:80546783
TEST=graphis autotest suite

Change-Id: I8d9c7fbc87fd80d03be7d9a98ac8aa95f0d175ed
Signed-off-by: Satyajit Sahu <satyajit.sahu@amd.com>
Reviewed-on: https://chromium-review.googlesource.com/1117975
Commit-Ready: Martin Roth <martinroth@chromium.org>
Tested-by: Martin Roth <martinroth@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>