crypto: powerpc/aes - assembler core

The assembler AES encryption and decryption core routines.
Implemented & optimized for big endian. Nevertheless they
work on little endian too.

For most efficient reuse in (higher level) block cipher
routines they are implemented as "fast" call modules without
any stack handling or register saving. The caller must
take care of that part.

Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>