cpufreq / intel_pstate: Set timer timeout correctly

The current calculation of the delay time is wrong and a cut and
paste error from a previous experimental driver. This can result in
the timeout being set to jiffies + 1 which setup the driver to race
with itself if the APIC timer interrupt happens at just the right
time.

References: https://bugzilla.redhat.com/show_bug.cgi?id=920289
Reported-by: Adam Williamson <[e-mail]>
Reported-and-tested-by: Parag Warudkar <[e-mail]>
Signed-off-by: Dirk Brandewie <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/intel_pstate.c

···
 
 	sample_time = cpu->pstate_policy->sample_rate_ms;
 	delay = msecs_to_jiffies(sample_time);
-	delay -= jiffies % delay;
 	mod_timer_pinned(&cpu->timer, jiffies + delay);
 }