Delete aesni_gcm_enc() and aesni_gcm_dec() because they are unused.
Only the incremental AES-GCM functions (aesni_gcm_init(),
aesni_gcm_enc_update(), aesni_gcm_finalize()) are actually used.

This saves 17 KB of object code.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>