drm/amdgpu: Modify the argument of emit_ib interface

use the point of struct amdgpu_job as the function
argument instand of vmid, so the other members of
struct amdgpu_job can be visit in emit_ib function.

v2: add a wrapper for getting the VMID
    add the job before the ib on the parameter list.
v3: refine the wrapper name

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>