crypto: cast5/cast6 - move lookup tables to shared module

CAST5 and CAST6 both use same lookup tables, which can be moved shared module
'cast_common'.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>