drm/amdgpu: use sched_job id instead of pointer for tracing

Pointers get reallocated and they are hard to read for humans. Use ids
instead.

Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>