LICENSES: Add the GPL 1.0 license

Add the full text of the GPL 1.0 license to the kernel tree.  It was
copied directly from:

       https://spdx.org/licenses/GPL-1.0.html#licenseText

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>