crypto: rockchip - ECB does not need IV

When loading rockchip crypto module, testmgr complains that ivsize of ecb-des3-ede-rk
is not the same than generic implementation.
In fact ECB does not use an IV.

Fixes: ce0183cb

 ("crypto: rockchip - switch to skcipher API")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>