cipher: constify spec arrays
* cipher/cipher.c (cipher_list): Constify array. * cipher/mac.c (mac_list): Constify array. * cipher/md.c (digest_list): Constify array. * cipher/pubkey.c (pubkey_list): Constify array.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>