crypto: testmgr - check skcipher min_keysize

When checking two implementations of the same skcipher algorithm for
consistency, require that the minimum key size be the same, not just the
maximum key size.  There's no good reason to allow different minimum key
sizes.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>