cpufreq: Update Documentation for cpus and related_cpus

Documentation related to cpus and related_cpus is confusing and not very clear.
Over that CPUFreq core has seen much changes recently. Lets update documentation
and comments for cpus and related_cpus.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 5fdc6c6..753b198 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -89,8 +89,10 @@
 };
 
 struct cpufreq_policy {
-	cpumask_var_t		cpus;	/* CPUs requiring sw coordination */
-	cpumask_var_t		related_cpus; /* CPUs with any coordination */
+	/* CPUs sharing clock, require sw coordination */
+	cpumask_var_t		cpus;	/* Online CPUs only */
+	cpumask_var_t		related_cpus; /* Online + Offline CPUs */
+
 	unsigned int		shared_type; /* ANY or ALL affected CPUs
 						should set cpufreq */
 	unsigned int		cpu;    /* cpu nr of CPU managing this policy */