There are some fixes listed below:
1. When met a bogus BIOS, the return value of cpu number maybe is
   a negative value so that acpi_pad_pur get an unexpected result.
2. the return value of function acpi_pad_idle_cpus is useless.
3. enhance the process of create_power_saving_task/destroy_power_saving_task
4. Add more error checks when evaluating _PUR object.
5. one typo fix
Signed-off-by: NChen Gong <gong.chen@linux.intel.com>
Acked-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>