Patch adds LRW support for serpent-sse2 by using lrw_crypt(). Patch has been
tested with tcrypt and automated filesystem tests.

Tcrypt benchmarks results (serpent-sse2/serpent_generic speed ratios):

Benchmark results with tcrypt:

Intel Celeron T1600 (x86_64) (fam:6, model:15, step:13):
size    lrw-enc lrw-dec
16B     1.00x   0.96x
64B     1.01x   1.01x
256B    3.01x   2.97x
1024B   3.39x   3.33x
8192B   3.35x   3.33x

AMD Phenom II 1055T (x86_64) (fam:16, model:10):
size    lrw-enc lrw-dec
16B     0.98x   1.03x
64B     1.01x   1.04x
256B    2.10x   2.14x
1024B   2.28x   2.33x
8192B   2.30x   2.33x

Intel Atom N270 (i586):
size    lrw-enc lrw-dec
16B     0.97x   0.97x
64B     1.47x   1.50x
256B    1.72x   1.69x
1024B   1.88x   1.81x
8192B   1.84x   1.79x
Signed-off-by: NJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Patch adds x86_64/SSE2 assembler implementation of serpent cipher. Assembler
functions crypt data in eigth block chunks (two 4 block chunk SSE2 operations
in parallel to improve performance on out-of-order CPUs). Glue code is based
on one from AES-NI implementation, so requests from irq context are redirected
to cryptd.

v2:
 - add missing include of linux/module.h
   (appearently crypto.h used to include module.h, which changed for 3.2 by
    commit 7c926402)

Patch has been tested with tcrypt and automated filesystem tests.

Tcrypt benchmarks results (serpent-sse2/serpent_generic speed ratios):

AMD Phenom II 1055T (fam:16, model:10):

size    ecb-enc ecb-dec cbc-enc cbc-dec ctr-enc ctr-dec
16B     1.03x   1.01x   1.03x   1.05x   1.00x   0.99x
64B     1.00x   1.01x   1.02x   1.04x   1.02x   1.01x
256B    2.34x   2.41x   0.99x   2.43x   2.39x   2.40x
1024B   2.51x   2.57x   1.00x   2.59x   2.56x   2.56x
8192B   2.50x   2.54x   1.00x   2.55x   2.57x   2.57x

Intel Celeron T1600 (fam:6, model:15, step:13):

size    ecb-enc ecb-dec cbc-enc cbc-dec ctr-enc ctr-dec
16B     0.97x   0.97x   1.01x   1.01x   1.01x   1.02x
64B     1.00x   1.00x   1.00x   1.02x   1.01x   1.01x
256B    3.41x   3.35x   1.00x   3.39x   3.42x   3.44x
1024B   3.75x   3.72x   0.99x   3.74x   3.75x   3.75x
8192B   3.70x   3.68x   0.99x   3.68x   3.69x   3.69x

Full output:
 http://koti.mbnet.fi/axh/kernel/crypto/phenom-ii-1055t/serpent-generic.txt
 http://koti.mbnet.fi/axh/kernel/crypto/phenom-ii-1055t/serpent-sse2.txt
 http://koti.mbnet.fi/axh/kernel/crypto/celeron-t1600/serpent-generic.txt
 http://koti.mbnet.fi/axh/kernel/crypto/celeron-t1600/serpent-sse2.txtSigned-off-by: NJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>