crypto: x86/sha - Intel SHA Extensions optimized SHA256 transform function

This patch includes the Intel SHA Extensions optimized implementation
of SHA-256 update function. This function has been tested on Broxton
platform and measured a speed up of 3.6x over the SSSE3 implementiation
for 4K blocks.

Originally-by: Chandramouli Narayanan <mouli_7982@yahoo.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>