Rafael observed [1] that returning 0 from processor_add() will result in
acpi_default_enumeration() being called which will attempt to create a
platform device, but that makes little sense when the processor is known
to be not available.  So just return the error code from acpi_processor_get_info()
instead.

Link: https://lore.kernel.org/all/CAJZ5v0iKU8ra9jR+EmgxbuNm=Uwx2m1-8vn_RAZ+aCiUVLe3Pw@mail.gmail.com/ [1]
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240529133446.28446-5-Jonathan.Cameron@huawei.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>