drm/amdgpu: Add reset control handling to reset workflow

This prefers reset control based handling if it's implemented
for a particular ASIC. If not, it takes the legacy path. It uses
the legacy method of preparing environment (job, scheduler tasks)
and restoring environment.

v2: remove unused variable (Alex)

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>