gnu-efi isn't making releases on SourceForge anymore, so switch to git
clones and track releases on GitHub.
License-Update: "Copright" typo fixed.
(From OE-Core rev: 958a1e5e911a3cd7912f9207528a2c9d61c2af6a)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>