drm/amdgpu/sdma4: add sdma4_0_1 support for vega12 (v3)

drm/amdgpu/sdma4: add sdma4_0_1 support for vega12 (v3)

Add sdma golden setting for vega12.

v2: switch to soc15_program_register_sequence for
golden register programming
v3: squash in unused declaration fix

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Feifei Xu <Feifei.Xu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>