drm/amdgpu: use multiple entities in amdgpu_move_blit

drm/amdgpu: use multiple entities in amdgpu_move_blit

Thanks to "drm/ttm: rework pipelined eviction fence handling", ttm
can deal correctly with moves and evictions being executed from
different contexts.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>