This patch adds support for the Chacha20-Poly1305 cipher suite.
It adds both the basic rfc7539(chacha20,poly1305) as well as the
rfc7539esp(chacha20,poly1305) variant for IPsec ESP acceleration.

changes since v1:
- rebased on top of DES library changes done on cryptodev/master
- fixed crypto/Kconfig so that generic fallback is compiled as well

changes since v2:
- nothing

changes since v3:
- Fixed a problem where the tcrypt performance test would run fully on the
  fallback cipher instead of the HW due to using an AAD length of 8 for
  rfc7539esp. While this is not actually legal ESP (which includes SPI and
  sequence number in the AAD as well), it is both inconvenient and not
  necessary to run these vectors on the fallback cipher.
- Due to above, also realised that for plain (non-ESP) rfc7539, you
  probably want to be able to run vectors with less than 8 bytes of AAD
  on the HW, and this is actually possible as long as cryptlen is large
  enough, so made that possible as well.
Signed-off-by: Pascal van Leeuwen <pvanleeuwen@verimatrix.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>