cpufreq: don't allow governor limits to be changed when it is disabled

__cpufreq_governor() returns with -EBUSY when governor is already
stopped and we try to stop it again, but when it is stopped we must
not allow calls to CPUFREQ_GOV_LIMITS event as well.

This patch adds this check in __cpufreq_governor().
Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq.c

@@ -1692,8 +1692,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 						policy->cpu, event);
 
 	mutex_lock(&cpufreq_governor_lock);
-	if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
-	    (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
+	if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
+	    || (!policy->governor_enabled
+	    && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
 		mutex_unlock(&cpufreq_governor_lock);
 		return -EBUSY;
 	}