Make vvu use devices use VFIO to manage their virt queues. This
alleviates the need to use noiommu mode. However, it is still necessary
to use `vfio_iommu_type1.allow_unsafe_interrupts=1`.
BUG=b:202151642,b:215310597
TEST=launch sibling with vvu + virtio-iommu
Cq-Depend: chromium:3565728, chromium:3565260
Change-Id: If418524598c40a37d41c0ffaa1dcc0f8ee11fcb3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3501052
Reviewed-by: Keiichi Watanabe <keiichiw@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: David Stevens <stevensd@chromium.org>