drm/amdgpu: add sdma block support for aldebaran

Add initial sdma support for aldebaran, and this asic has 5 sdma instances.

v2: remove adundant condition check

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