drm/amdgpu: move UVD and VCE sched entity init after sched init

We need kernel scheduling entities to deal with handle clean up
if apps are not cleaned up properly.  With commit 56e44960
("drm/sched: Convert the GPU scheduler to variable number of run-queues")
the scheduler entities have to be created after scheduler init, so
change the ordering to fix this.

v2: Leave logic in UVD and VCE code

Fixes: 56e44960

 ("drm/sched: Convert the GPU scheduler to variable number of run-queues")
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Luben Tuikov <ltuikov89@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: ltuikov89@gmail.com