utils: util: fix incorrect module import

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

utils/util.py

diff --git a/utils/util.py b/utils/util.py
index 1bbbfb4..5fec063 100644
--- a/utils/util.py
+++ b/utils/util.py
@@ -2,7 +2,7 @@
 import os
 import random
 import re
-from roi import Roi
+from .roi import Roi
 from jinja2 import Environment, FileSystemLoader
 
 def get_jinja_template(tpl_file, directory = "./"):