The stand-alone application "contrib/itmdump.c" is released as
GPL-3.0-or-later.
Add GPL-3.0 license in the licenses list.
Copy in subfolder stand-alone the GPL-3.0 from
https://www.gnu.org/licenses/gpl-3.0.txt
adding the header required by spdxcheck.py.
Change-Id: I238efc411e07ed6bc1eba23edbc91b3825c3d2c7
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5968
Tested-by: jenkins
Antonio Borneo