add top-level SPDX license tag

This patch adds top level SPDX license identifiers for some of the DPDK
source and scripts, where the copyright owners have not yet agreed to
replace the full BSD-3 license plate.

This patch also add SPDX license tag for a file with no
previous license plates. (DPDK is BSD-3)

Signed-off-by: Hemant Agrawal <hemant.agrawal@nxp.com>

app/test/test_compressdev_test_buffer.h

@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: (BSD-3-Clause)
+/* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2018-2020 Intel Corporation
  */
 

app/test/test_timer_racecond.c

@@ -1,6 +1,4 @@
-/*-
- *   BSD LICENSE
- *
+/* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2015 Akamai Technologies.
  * All rights reserved.
  *

examples/performance-thread/l3fwd-thread/test.sh

@@ -1,4 +1,5 @@
 #!/bin/bash
+# SPDX-License-Identifier: BSD-3-Clause
 
 case "$1" in
 

lib/librte_ethdev/rte_ethdev_pci.h

@@ -1,6 +1,4 @@
-/*-
- *   BSD LICENSE
- *
+/* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2017 Brocade Communications Systems, Inc.
  *   Author: Jan Blunck <jblunck@infradead.org>
  *

lib/librte_ethdev/rte_ethdev_vdev.h

@@ -1,6 +1,4 @@
-/*-
- *   BSD LICENSE
- *
+/* SPDX-License-Identifier: BSD-3-Clause
  * Copyright(c) 2017 Brocade Communications Systems, Inc.
  *   Author: Jan Blunck <jblunck@infradead.org>
  *