drm/amdgpu: Convert update_partition_sched_list into a common helper v3

drm/amdgpu: Convert update_partition_sched_list into a common helper v3

The update_partition_sched_list function does not
need to remain as a soc specific callback. It can
be reused for future products.

v2: bypass the function if xcp_mgr is not available (Likun)

v3: Let caller check the availability of xcp_mgr (Lijo)

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>