drm/amdgpu: add soc15 common ip block support for green_sardine (v3)

This patch adds common ip support for green_sardine.

v2: use apu flags, squash in CG/PG enablement
v3: rebase

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>