rcu: Move early boot callback tests earlier

Because callbacks can now be posted quite early in boot, move the
early boot callback tests to precede RCU initialization.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -3948,6 +3948,8 @@ void __init rcu_init(void)
 {
 	int cpu;
 
+	rcu_early_boot_tests();
+
 	rcu_bootup_announce();
 	rcu_init_geometry();
 	rcu_init_one(&rcu_bh_state, &rcu_bh_data);
@@ -3964,8 +3966,6 @@ void __init rcu_init(void)
 	pm_notifier(rcu_pm_notify, 0);
 	for_each_online_cpu(cpu)
 		rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-
-	rcu_early_boot_tests();
 }
 
 #include "tree_plugin.h"