drm/amdgpu: remove some more semaphore leftovers

No longer needed since semaphores were removed.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <David1.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
12 files changed