crypto: ctr - no longer needs CRYPTO_SEQIV

As comment of the v2, Herbert said: "The SEQIV select from CTR is historical
and no longer necessary."

So let's get rid of it.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>