[magma] Support for querying engines

Just hardcoded for now, this should eventually query the MSD.
Also add stub support for load balancing so even though we only
support one video engine, we handle the change in command buffer
submit semantics.

Bug:110484

Change-Id: If80f565fbc28d102e5d99ae6fa0fdfb53695a423
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/github.com/intel/media-driver/+/731822
Reviewed-by: John Bauman <jbauman@google.com>
2 files changed