cpufreq / intel_pstate: Fix calculation of current frequency

Use the correct pstate value to calculate the effective frequency.

References: https://bugzilla.redhat.com/show_bug.cgi?id=923942Reported-by: NSatish Balay <balay@fastmail.fm>
Signed-off-by: NDirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/intel_pstate.c

@@ -454,7 +454,7 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu,
 					sample->idletime_us * 100,
 					sample->duration_us);
 	core_pct = div64_u64(sample->aperf * 100, sample->mperf);
-	sample->freq = cpu->pstate.turbo_pstate * core_pct * 1000;
+	sample->freq = cpu->pstate.max_pstate * core_pct * 1000;
 
 	sample->core_pct_busy = div_s64((sample->pstate_pct_busy * core_pct),
 					100);