crypto: cts - Remove bogus use of seqiv

The seqiv generator is completely inappropriate for cts as it's
designed for IPsec algorithms.  Since cts users do not actually
use the IV generator we can just fall back to the default.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Maciej ?enczykowski <zenczykowski@gmail.com>