drm/amdgpu: add aldebaran sdma firmware support (v2)

add sdma firmware load support for soc model

v2: drop some emulator leftovers (Alex)

Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Le Ma <Le.Ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>