drm/admgpu: Skip CG/PG on SOC21 under SRIOV VF

[Why]
There is no CG(Clock Gating)/PG(Power Gating) requirement on SRIOV VF.
For multi VF, VF should not enable any CG/PG features.
For one VF, PF will program CG/PG related registers.

[How]
Do not set any cg/pg flag bit at early init under sriov.

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