ovl: fix tmpfile leak

Missed an error cleanup.

Reported-by: syzbot+fd749a7ea127a84e0ffd@syzkaller.appspotmail.com
Fixes: 2b1a7746 ("ovl: use vfs_tmpfile_open() helper")
Cc: <stable@vger.kernel.org> # v6.1
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/copy_up.c

@@ -792,7 +792,7 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
 	if (!c->metacopy && c->stat.size) {
 		err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size);
 		if (err)
-			return err;
+			goto out_fput;
 	}
 
 	err = ovl_copy_up_metadata(c, temp);