external: add missing Samsung Apache license at Makefile
This Makefile was made by Samsung so that we add Samsung Copyright and License.
############################################################################
+#
+# Copyright 2016 Samsung Electronics All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+# either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+#
+############################################################################
+############################################################################
# external/Makefile
#
# Copyright (C) 2007, 2008, 2011-2015 Gregory Nutt. All rights reserved.
