gfxstream: nuke mWorkPool

Added via:

https://android-review.git.corp.google.com/q/topic:%22vulkan-android-external-fence-sync-fd%22

Ideally, we'd avoided complex thread pools in a VK driver.
Plus, virtio-gpu needs synchronization changes anyways.

      - dEQP-VK.api.external.semaphore.sync_fd*

Reviewed-by: Aaron Ruby <aruby@blackberry.com>
Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Acked-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27246>
2 files changed