Upstream commit 997fa5ba1e14b52c554fb03ce39e579e6f27b90c,
git repository: git://github.com/BLAKE2/BLAKE2
The reference implemetation added in this patch is unchanged and will be
modified only to compile in current code base and with minimal other
modifications in case of future sync with upstream code. IOW, the coding
style should stay as-is and does not conform to the other btrfs-progs
code. This is an exception for xxhash and sha256 code as well.
Signed-off-by: David Sterba <dsterba@suse.com>
