crypto: blowfish - add x86_64 assembly implementation

Patch adds x86_64 assembly implementation of blowfish. Two set of assembler
functions are provided. First set is regular 'one-block at time'
encrypt/decrypt functions. Second is 'four-block at time' functions that
gain performance increase on out-of-order CPUs. Performance of 4-way
functions should be equal to 1-way functions with in-order CPUs.

Summary of the tcrypt benchmarks:

Blowfish assembler vs blowfish C (256bit 8kb block ECB)
encrypt: 2.2x speed
decrypt: 2.3x speed

Blowfish assembler vs blowfish C (256bit 8kb block CBC)
encrypt: 1.12x speed
decrypt: 2.5x speed

Blowfish assembler vs blowfish C (256bit 8kb block CTR)
encrypt: 2.5x speed

Full output:
http://koti.mbnet.fi/axh/kernel/crypto/tcrypt-speed-blowfish-asm-x86_64.txt
http://koti.mbnet.fi/axh/kernel/crypto/tcrypt-speed-blowfish-c-x86_64.txt



Tests were run on:
 vendor_id	: AuthenticAMD
 cpu family	: 16
 model		: 10
 model name	: AMD Phenom(tm) II X6 1055T Processor
 stepping	: 0

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>