fix(demo): Add default number of CPU threads in the layout demo.

Signed-off-by: Nikos Livathinos <[email protected]>

demo/demo_layout_predictor.py

@@ -136,7 +136,7 @@ def main(args):
         "-d", "--device", required=False, default="cpu", help="One of [cpu, cuda, mps]"
     )
     parser.add_argument(
-        "-n", "--num_threads", required=False, default=None, help="Number of threads"
+        "-n", "--num_threads", required=False, default=4, help="Number of threads"
     )
     parser.add_argument(
         "-i",