Add license to plot utility

Author: SoilRos

cpu_latency_plot

@@ -1,5 +1,41 @@
 #!/usr/bin/env python3
 
+# The MIT License (MIT)
+
+# Copyright (c) 2022 Nicolas Viennot
+
+# Permission is hereby granted, free of charge, to any
+# person obtaining a copy of this software and associated
+# documentation files (the "Software"), to deal in the
+# Software without restriction, including without
+# limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software
+# is furnished to do so, subject to the following
+# conditions:
+
+# The above copyright notice and this permission notice
+# shall be included in all copies or substantial portions
+# of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+# ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+# TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+# SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+# IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+# DEALINGS IN THE SOFTWARE.
+
+
+# This file was originally part of core-to-core-latency by Nicolas Viennot.
+#
+# Modifications have been made to this file by the cpu_latency project.
+#
+# The modified version is licensed under the MIT License.
+# See the LICENSE file in the root directory of this source tree for more information.
+
 import matplotlib.pyplot as plt
 from matplotlib import colormaps as cmaps
 import numpy as np