tools/power/cpupower enhancements/fixes

[Thomas Renninger <trenn@xxxxxxx>]

New functionality:
  - cpupower idle-set
    gets two new parameters:
       -D <LATENCY>
    -> To disable all C-states with a latency higher or equal LATENCY
       -E
    -> enable all C-states if not enabled already. The counterpart to above
       to get back to default

Rest are easy bugfixes.

Rafael: Would you mind queuing these patches for the next release, please.

Thanks,

       Thomas