Add interface to get ACPI device associated with the
PMU. This ACPI device may contain additional properties
not covered by the standard properties.
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>