drm/amdgpu/sdma: add sdma engine support for green_sardine (v2)

Initialize the SDMA IP for green_sardine.

v2: use apu flags

Signed-off-by: Prike Liang <Prike.Liang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>