minigbm: Align BO tile size for llvmpipe on dumb driver

Mesa's llvmpipe software renderer generates instructions that require
memory to be aligned properly, otherwise it will crash with general
protection exception. To support crosvm on headless VM with vkms we'd
like to always align memory properly on dumb driver.

BUG=b:239110721
TEST=Run betty-arc-r on headless VM with vkms enabled

Change-Id: I4b119f450cbb9b36d0d35d37be9ca97102924963
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/4134929
Tested-by: Yi Xie <yixie@chromium.org>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Commit-Queue: Yi Xie <yixie@chromium.org>
3 files changed