crypto: sha512 - Optimized SHA512 x86_64 assembly routine using AVX2 RORX instruction.

Provides SHA512 x86_64 assembly routine optimized with SSE, AVX and
AVX2's RORX instructions.  Speedup of 70% or more has been
measured over the generic implementation.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>