drm/amd: Only run s3 or s0ix if system is configured properly

This will cause misconfigured systems to not run the GPU suspend
routines.

* In APUs that are properly configured system will go into s2idle.
* In APUs that are intended to be S3 but user selects
  s2idle the GPU will stay fully powered for the suspend.
* In APUs that are intended to be s2idle and system misconfigured
  the GPU will stay fully powered for the suspend.
* In systems that are intended to be s2idle, but AMD dGPU is also
  present, the dGPU will go through S3

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>