cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

When we don't have any file in cpu/cpufreq directory we shouldn't
create it. Specially with the introduction of per-policy governor
instance patchset, even governors are moved to
cpu/cpu*/cpufreq/governor-name directory and so this directory is
just not required.

Lets have it only when required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 11b8b4b..8c02622 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -947,7 +947,7 @@
 	/* We create the boost file in any case, though for systems without
 	 * hardware support it will be read-only and hardwired to return 0.
 	 */
-	if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
+	if (cpufreq_sysfs_create_file(&(global_boost.attr)))
 		pr_warn(PFX "could not register global boost sysfs file\n");
 	else
 		pr_debug("registered global boost sysfs file\n");
@@ -955,7 +955,7 @@
 
 static void __exit acpi_cpufreq_boost_exit(void)
 {
-	sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
+	cpufreq_sysfs_remove_file(&(global_boost.attr));
 
 	if (msrs) {
 		unregister_cpu_notifier(&boost_nb);