drm/msm: Conversion to drm scheduler

drm/msm: Conversion to drm scheduler

For existing adrenos, there is one or more ringbuffer, depending on
whether preemption is supported.  When preemption is supported, each
ringbuffer has it's own priority.  A submitqueue (which maps to a
gl context or vk queue in userspace) is mapped to a specific ring-
buffer at creation time, based on the submitqueue's priority.

Each ringbuffer has it's own drm_gpu_scheduler.  Each submitqueue
maps to a drm_sched_entity.  And each submit maps to a drm_sched_job.

Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/4
Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20210728010632.2633470-10-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>