rcu: Wire up rcu_end_inkernel_boot()

This commit adds the invocation of rcu_end_inkernel_boot() just before
init is invoked.  This allows the CONFIG_RCU_EXPEDITE_BOOT Kconfig
option to do something useful and prepares for the upcoming
rcupdate.rcu_normal_after_boot kernel parameter.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

init/main.c

@@ -943,6 +943,8 @@ static int __ref kernel_init(void *unused)
 
 	flush_delayed_fput();
 
+	rcu_end_inkernel_boot();
+
 	if (ramdisk_execute_command) {
 		ret = run_init_process(ramdisk_execute_command);
 		if (!ret)