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/omfs/inode.c b/fs/omfs/inode.c
index 6065bb0..dbc8422 100644
--- a/fs/omfs/inode.c
+++ b/fs/omfs/inode.c
@@ -539,11 +539,9 @@
 		goto out_brelse_bh2;
 	}
 
-	sb->s_root = d_alloc_root(root);
-	if (!sb->s_root) {
-		iput(root);
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root)
 		goto out_brelse_bh2;
-	}
 	printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 
 	ret = 0;