drm/amdgpu: Add per device sdma_doorbell_range field

Different ASIC has different sdma doorbell range. Add
a per device sdma_doorbell_range field and initialize
it.

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>