nilfs2: add a print message after loading nilfs2

Printing a message after loading a file system is a practice. Add this to
provide a better user-friendly experience.
Signed-off-by: Li Hong <lihong.hi@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

fs/nilfs2/super.c

@@ -1190,6 +1190,7 @@ static int __init init_nilfs_fs(void)
 	if (err)
 		goto free_cachep;
 
+	printk(KERN_INFO "NILFS version 2 loaded\n");
 	return 0;
 
 free_cachep: