crypto: camellia-x86_64 - share common functions and move structures and function definitions to header file

Prepare camellia-x86_64 functions to be reused from AVX/AESNI implementation
module.
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>