Check assoclen to solve the extra tests that expect -EINVAL to be
returned when the associated data size is not valid.

Validated assoclen for RFC4106 and RFC4543 which expects an assoclen
of 16 or 20.
Based on seqiv, IPsec ESP and RFC4543/RFC4106 the assoclen is sizeof IP
Header (spi, seq_no, extended seq_no) and IV len. This can be 16 or 20
bytes.
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Reviewed-by: Horia Geanta <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>