Power management fixes for v4.13-rc6

 - Disable interrupts around reading IA32_APERF and IA32_MPERF in
   aperfmperf_snapshot_khz() (introduced recently) to avoid excessive
   delays between the reads that may result from interrupt handling
   (Doug Smythies).

 - Fix the comutation of the CPU frequency to be reported through the
   pstate_sample tracepoint in intel_pstate (Doug Smythies).
Merge branches 'intel_pstate-fix' and 'cpufreq-x86-fix'

* intel_pstate-fix:
  cpufreq: intel_pstate: report correct CPU frequencies during trace

* cpufreq-x86-fix:
  cpufreq: x86: Disable interrupts during MSRs reading