crypto: hifn_795x - Remove unused hifn_*_command structs

Remove 'hifn_mac_command' and 'hifn_comp_command' which are unused.
They're the same structure as 'hifn_crypt_command' which is used.

(I was tempted to remove
   hifn_base_result
   hifn_comp_result
   hifn_mac_result and
   hifn_crypt_result
which are also unused, but they vary, and perhaps they're telling
someone in the future what to look at.)

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>