drm/amdgpu: Place NPS mode request on unload

If a user has requested NPS mode switch, place the request through PSP
during unload of the driver. For devices which are part of a hive, all
requests are placed together. If one of them fails, revert back to the
current NPS mode.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>