ovl: remove unneeded check for IS_ERR()

ovl_workdir_create() returns a valid index dentry or NULL.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/super.c

@@ -1058,10 +1058,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 		ufs->indexdir = ovl_workdir_create(sb, ufs, workpath.dentry,
 						   OVL_INDEXDIR_NAME, true);
-		err = PTR_ERR(ufs->indexdir);
-		if (IS_ERR(ufs->indexdir))
-			goto out_put_lower_mnt;
-
 		if (ufs->indexdir) {
 			/* Verify upper root is index dir origin */
 			err = ovl_verify_origin(ufs->indexdir, ufs->upper_mnt,