[CRYPTO] geode: Add fallback for unsupported modes

The Geode AES crypto engine supports only 128 bit long key. This
patch adds fallback for other key sizes which are required by the
AES standard.

Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>