drm/amdgpu: correct rlc save restore list initialization for v2_1

The save restore list initialization does not have to be pg guarded.
And for some asic(e.g. Vega12), it does not have cntl/gpm/srm lists.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>