Optimize raw SHA512 to be ready to latest driver (14.6beta).
Move shared macros to the header file.
Small tweaks.
Remove more unnecessary code.
Shrink the kernel  a little bit more.
Remove one unused var.
Clean raw SHA256 code.
Rewrite some comments.
Remove one unnecessary math operation.
Merge pull request #737 from claudioandre/bleeding-jumbo

Optimize raw SHA2 to be ready to latest driver (14.6beta).