Add a new driver internal interface for accessing ACPI
methods.  These will be used by various new components
including powerplay.
Signed-off-by: NRex Zhu <Rex.Zhu@amd.com>
Reviewed-by: NJammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>