util: Add SPDX header, replacing boiler plate where applicable

In a few cases a license was added: Stuff coming from Linux is
"GPL-2.0" (not GPL-2.0-only!), build-release is by me and got the
usual GPL-2.0-only treatment. uio_usbdebug and spkmodem had their
licenses propagate to all their files.

Change-Id: Ia5712bbaa417cb9e937834512351fcc0acfa16be
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41202
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/rockchip/make_idb.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python2
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
+# SPDX-License-Identifier: BSD-2-Clause
 
 import struct
 import sys