ACPI: processor: open code acpi_processor_cleanup_pdc

We have the acpi_object_list * right there in acpi_processor_set_pdc()
so it doesn't seem necessary for an entire helper function just to
free it.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>