crypto: essiv - add tests for essiv in cbc(aes)+sha256 mode

Add a test vector for the ESSIV mode that is the most widely used,
i.e., using cbc(aes) and sha256, in both skcipher and AEAD modes
(the latter is used by tcrypt to encapsulate the authenc template
or h/w instantiations of the same)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>