Use straightforward (buffer, len) parameters instead of struct
drbg_string or lists of strings. This simplifies the code considerably.
For now struct drbg_string is still used in crypto_drbg_ctr_df(), so
move its definition to crypto/df_sp80090a.h.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>