crypto: p10-aes-gcm - Supporting functions for ghash

This perl code is taken from the OpenSSL project and added gcm_init_htable function
used in the aes-gcm-p10-glue.c code to initialize hash table.  gcm_hash_p8 is used
to hash encrypted data blocks.

Signed-off-by: Danny Tsen <dtsen@linux.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>