Fix benchmark.py usage comment (#10131)

Update benchmarks.py

Signed-off-by: Rubén Usamentiaga <rusamentiaga@uniovi.es>

Signed-off-by: Rubén Usamentiaga <rusamentiaga@uniovi.es>

benchmarks.py

@@ -22,7 +22,7 @@
     $ pip install -U nvidia-tensorrt --index-url https://pypi.ngc.nvidia.com  # TensorRT
 
 Usage:
-    $ python utils/benchmarks.py --weights yolov5s.pt --img 640
+    $ python benchmarks.py --weights yolov5s.pt --img 640
 """
 
 import argparse