platform: migrate to SPDX identifier

Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>

platform/CMakeLists.txt

@@ -1,6 +1,8 @@
 # ##############################################################################
 # apps/platform/CMakeLists.txt
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more contributor
 # license agreements.  See the NOTICE file distributed with this work for
 # additional information regarding copyright ownership.  The ASF licenses this

platform/Make.defs

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/platform/Make.defs
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

platform/Makefile

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/platform/Makefile
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

platform/bin/Makefile

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/platform/bin/Makefile
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

platform/dummy/Make.defs

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/platform/dummy/Make.defs
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

platform/dummy/dummy.c

@@ -1,6 +1,8 @@
 /***************************************************************************
  * apps/platform/dummy/dummy.c
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.  The

platform/mikroe-stm32f4/Make.defs

@@ -1,6 +1,8 @@
 ############################################################################
 # apps/platform/mikroe-stm32f4/Make.defs
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.  The

platform/mikroe-stm32f4/mikroe_configdata.c

@@ -1,6 +1,8 @@
 /****************************************************************************
  * apps/platform/mikroe-stm32f4/mikroe_configdata.c
  *
+ * SPDX-License-Identifier: Apache-2.0
+ *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.  The