sched: Fix return value of migration_init()

migration_init() returns the return value of the hotplug notifier. In
the success case this is NOTIFY_OK which is 1. initcall_debug
evaluates that as an error code because init calls are expected to
return 0 on success.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/sched.c b/kernel/sched.c
index 1f7919a..953f037 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7654,7 +7654,7 @@
 	migration_call(&migration_notifier, CPU_ONLINE, cpu);
 	register_cpu_notifier(&migration_notifier);
 
-	return err;
+	return 0;
 }
 early_initcall(migration_init);
 #endif