cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered

Make pcc_cpufreq_init() return error codes when the driver cannot be
registered.  Otherwise the driver can shows up loaded via lsmod even
though it failed initialization.  This is confusing to the user.
Signed-off-by: David Arcari <darcari@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/pcc-cpufreq.c

@@ -582,10 +582,10 @@ static int __init pcc_cpufreq_init(void)
 
 	/* Skip initialization if another cpufreq driver is there. */
 	if (cpufreq_get_current_driver())
-		return 0;
+		return -EEXIST;
 
 	if (acpi_disabled)
-		return 0;
+		return -ENODEV;
 
 	ret = pcc_cpufreq_probe();
 	if (ret) {