drm/amdgpu: skip VCN2.5 power gating and clock gating for sriov Arcturus

v1: skip gating in serveral called functions by power gating and clock gating
v2: from suggestion, skip setting gate in both set function, which is where
it being called.

Signed-off-by: Jane Jian <Jane.Jian@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>