Add LICENSE files and SPDX tags

LICENSES/BSD-3-Clause.txt

@@ -0,0 +1,26 @@
+Copyright (c) <year> <owner>. 
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

LICENSES/LicenseRef-nrf_common.txt

@@ -0,0 +1,11 @@
+ * Copyright (c) 2007, 2008, 2009, 2010 CodeSourcery, Inc.
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions.  No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.

third_party/nrfx-custom/nrf52840_xxaa.ld

@@ -1,3 +1,6 @@
+/* SPDX-FileCopyrightText: Nordic Semiconductor ASA
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
 /* Linker script to configure memory regions. */
 
 SEARCH_DIR(.)

third_party/nrfx-custom/nrf_common.ld

@@ -4,6 +4,7 @@
  * Support: https://support.codesourcery.com/GNUToolchain/
  *
  * Copyright (c) 2007, 2008, 2009, 2010 CodeSourcery, Inc.
+ * SPDX-License-Identifier: LicenseRef-nrf_common
  *
  * The authors hereby grant permission to use, copy, modify, distribute,
  * and license this software and its documentation for any purpose, provided