libfdt: Replace GPL/BSD boilerplate/reference with SPDX tags

Replace instances of dual GPLv2 or BSD license boilerplate with SPDX tags.

Signed-off-by: Rob Herring <robh@kernel.org>
Message-Id: <20190620211944.9378-3-robh@kernel.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
13 files changed