[CRYPTO] tcrypt: Support for large test vectors

Currently the number of entries in a cipher test vector template is
limited by TVMEMSIZE/sizeof(struct cipher_testvec). This patch
circumvents the problem by pointing cipher_tv to each entry in the
template, rather than the template itself.

Signed-off-by: Tan Swee Heng <thesweeheng@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>