vela: Update tool description text

 - Updated and aligned the --help and setup.py descriptions

Signed-off-by: Tim Hall <tim.hall@arm.com>
Change-Id: I78c11b1b3dd51284b34d57a6caca45cd222b4678
diff --git a/setup.py b/setup.py
index 1ab8dd5..d3a1013 100644
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
 setup(
     name="ethos-u-vela",
     use_scm_version=True,
-    description="Optimise TensorFlow Lite models for Ethos-U NPU.",
+    description="Neural network model compiler for Arm Ethos-U NPUs",
     long_description=long_description,
     long_description_content_type="text/markdown",
     url="https://git.mlplatform.org/ml/ethos-u/ethos-u-vela.git/",