Add support for high priority scheduling in amdgpu v6

[Andres Rodriguez]

Forgot to mention, lockdep was clean with the following options enabled:

[*] Spinlock and rw-lock debugging: basic checks
[*] Mutex debugging: basic checks
[*] Sleep inside atomic section checking

Regards,
Andres

On 2017-03-07 06:50 PM, Andres Rodriguez wrote:
> Updated with Christian and Alex's feedback.
>
> Also added missing initialization of ring->num_jobs[] to PATCH 18
>
> Added a new patch:
> [PATCH 19/22] drm/amdgpu: convert srbm lock to a spinlock
>
> Also some new benchmarks for the high priority queue using a modified
> computeparticles that only takes 0.2ms to execute:
> https://plot.ly/~lostgoat/15/
>
> The 0.2ms time was picked as an estimate of how long the reprojection
> task would take to execute.
>