crypto: crypto4xx - set CRYPTO_ALG_KERN_DRIVER_ONLY flag

The security offload function is performed by a cryptographic
engine core attached to the 128-bit PLB (processor local bus)
with builtin DMA and interrupt controllers. This, I think,
satisfies the requirement for the CRYPTO_ALG_KERN_DRIVER_ONLY
flag.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>