cpufreq: cpufreq_register_driver() should return -ENODEV if init fails

For a driver that does not set the CPUFREQ_STICKY flag, if all of the
->init() calls fail, cpufreq_register_driver() should return an error.
This will prevent the driver from loading.

Fixes: ce1bcfe94db8 (cpufreq: check cpufreq_policy_list instead of scanning policies for all CPUs)
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
Signed-off-by: David Arcari <darcari@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq.c

@@ -2468,6 +2468,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 	if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
 	    list_empty(&cpufreq_policy_list)) {
 		/* if all ->init() calls failed, unregister */
+		ret = -ENODEV;
 		pr_debug("%s: No CPU initialized for driver %s\n", __func__,
 			 driver_data->name);
 		goto err_if_unreg;