[CRYPTO] lrw: Liskov Rivest Wagner, a tweakable narrow block cipher mode

[CRYPTO] lrw: Liskov Rivest Wagner, a tweakable narrow block cipher mode

Main module, this implements the Liskov Rivest Wagner block cipher mode
in the new blockcipher API. The implementation is based on ecb.c.

The LRW-32-AES specification I used can be found at:
http://grouper.ieee.org/groups/1619/email/pdf00017.pdf

It implements the optimization specified as optional in the
specification, and in addition it uses optimized multiplication
routines from gf128mul.c.

Since gf128mul.[ch] is not tested on bigendian, this cipher mode
may currently fail badly on bigendian machines.

Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>