crypto: iaa - Use kmemdup() instead of kzalloc() and memcpy()

Fixes the following two Coccinelle/coccicheck warnings reported by
memdup.cocci:

	iaa_crypto_main.c:350:19-26: WARNING opportunity for kmemdup
	iaa_crypto_main.c:358:18-25: WARNING opportunity for kmemdup

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>