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/udf/super.c b/fs/udf/super.c
index 8d8b253..85067b4 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -2037,10 +2037,9 @@
 	}
 
 	/* Allocate a dentry for the root inode */
-	sb->s_root = d_alloc_root(inode);
+	sb->s_root = d_make_root(inode);
 	if (!sb->s_root) {
 		udf_err(sb, "Couldn't allocate root dentry\n");
-		iput(inode);
 		goto error_out;
 	}
 	sb->s_maxbytes = MAX_LFS_FILESIZE;