drm/amdgpu: add master/slave check in init phase

Skip KCQ setup on slave xcc as there's no use case.

Signed-off-by: Le Ma <le.ma@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>