cpufreq: Restore policy min/max limits on CPU online

On CPU online the cpufreq core restores the previous governor (or
the previous "policy" setting for ->setpolicy drivers), but it does
not restore the min/max limits at the same time, which is confusing,
inconsistent and real pain for users who set the limits and then
suspend/resume the system (using full suspend), in which case the
limits are reset on all CPUs except for the boot one.

Fix this by making cpufreq_online() restore the limits when an inactive
policy is brought online.

The commit log and patch are inspired from Rafael's earlier work.

Reported-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.3+ <stable@vger.kernel.org> # 4.3+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq.c

@@ -1184,6 +1184,9 @@ static int cpufreq_online(unsigned int cpu)
 		for_each_cpu(j, policy->related_cpus)
 			per_cpu(cpufreq_cpu_data, j) = policy;
 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+	} else {
+		policy->min = policy->user_policy.min;
+		policy->max = policy->user_policy.max;
 	}
 
 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {