acpi-cpufreq: Fail initialization if driver cannot be registered

Make acpi_cpufreq_init() return error codes when the driver cannot be
registered so that the module doesn't stay useless in memory and so
that acpi_cpufreq_exit() doesn't attempt to unregister things that
have never been registered when the module is unloaded.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/acpi-cpufreq.c

@@ -986,12 +986,12 @@ static int __init acpi_cpufreq_init(void)
 {
 	int ret;
 
+	if (acpi_disabled)
+		return -ENODEV;
+
 	/* don't keep reloading if cpufreq_driver exists */
 	if (cpufreq_get_current_driver())
-		return 0;
-
-	if (acpi_disabled)
-		return 0;
+		return -EEXIST;
 
 	pr_debug("acpi_cpufreq_init\n");