switch open-coded instances of d_make_root() to new helper

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/efs/super.c b/fs/efs/super.c
index 9811064..e755ec7 100644
--- a/fs/efs/super.c
+++ b/fs/efs/super.c
@@ -317,10 +317,9 @@
 		goto out_no_fs;
 	}
 
-	s->s_root = d_alloc_root(root);
+	s->s_root = d_make_root(root);
 	if (!(s->s_root)) {
 		printk(KERN_ERR "EFS: get root dentry failed\n");
-		iput(root);
 		ret = -ENOMEM;
 		goto out_no_fs;
 	}