Convert to new copyright header format

The new Code Climate header check expects the following header format:

   SPDX-FileCopyrightText: <text>Copyright YYYY(-YYYY)
   [Copyright holder] <[Email address]></text>
   SPDX-License-Identifier: <LicenseID>

Convert all files to the new format.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>