tools/power/x86: Debug utility for intel_pstate driver

This utility can be used to debug and tune the performance of the
intel_pstate driver.

This utility can be used in two ways:

 - If there is Linux trace file with pstate_sample events enabled, then
   this utility can parse the trace file and generate performance plots.

 - If user has not specified a trace file as input via command line
   parameters, then this utility enables and collects trace data for a
   user-specified interval and generates performance plots.

Signed-off-by: Doug Smythies <dsmythies@telus.net>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>