drm/amdgpu: assign different AMDGPU_GFXHUB for rings on each xcc

Pass the xcc_id to AMDGPU_GFXHUB(x)

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