Revert "Call init_workqueues before pre smp initcalls."

This reverts commit a802dd0eb5fc97a50cf1abb1f788a8f6cc5db635 by moving
the call to init_workqueues() back where it belongs - after SMP has been
initialized.

It also moves stop_machine_init() - which needs workqueues - to a later
phase using a core_initcall() instead of early_initcall().  That should
satisfy all ordering requirements, and was apparently the reason why
init_workqueues() was moved to be too early.

Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/main.c

@@ -768,6 +768,7 @@ static void __init do_initcalls(void)
 static void __init do_basic_setup(void)
 {
 	rcu_init_sched(); /* needed by module_init stage. */
+	init_workqueues();
 	usermodehelper_init();
 	driver_init();
 	init_irq_proc();
@@ -851,8 +852,6 @@ static int __init kernel_init(void * unused)
 
 	cad_pid = task_pid(current);
 
-	init_workqueues();
-
 	smp_prepare_cpus(setup_max_cpus);
 
 	do_pre_smp_initcalls();

kernel/stop_machine.c

@@ -160,4 +160,4 @@ static int __init stop_machine_init(void)
 	stop_machine_work = alloc_percpu(struct work_struct);
 	return 0;
 }
-early_initcall(stop_machine_init);
+core_initcall(stop_machine_init);