drm/amdgpu: remove fence parameter from amd_sched_job_init

We return the fence as part of the job structur anyway,
no need to do this twice.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>