[PATCH] LRU map compute/SDMA user ring ids to kernel ring ids v2

[Andres Rodriguez]

V2 updates:
 * Rebased
 * All patches now have r-b

Second part of the split of the series:
Add support for high priority scheduling in amdgpu v8

These patches should be close to being good enough to land.

The first two patches are simple fixes I've ported from the ROCm branch. These
still need review.

I've fixed all of Christian's comments for patch 04:
drm/amdgpu: implement lru amdgpu_queue_mgr policy for compute v4