[CRYPTO] seed: New cipher algorithm

This patch adds support for the SEED cipher (RFC4269).

This patch have been used in few VPN appliance vendors in Korea for
several years.  And it was verified by KISA, who developed the
algorithm itself.

As its importance in Korean banking industry, it would be great
if linux incorporates the support.

Signed-off-by: Hye-Shik Chang <perky@FreeBSD.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>