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/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c
index 9d1c995..d4fabd2 100644
--- a/fs/freevxfs/vxfs_super.c
+++ b/fs/freevxfs/vxfs_super.c
@@ -224,9 +224,8 @@
 		ret = PTR_ERR(root);
 		goto out;
 	}
-	sbp->s_root = d_alloc_root(root);
+	sbp->s_root = d_make_root(root);
 	if (!sbp->s_root) {
-		iput(root);
 		printk(KERN_WARNING "vxfs: unable to get root dentry.\n");
 		goto out_free_ilist;
 	}