crypto: caam - Use ahash_request_complete

Instead of calling the base completion function directly, use the
correct ahash helper which is ahash_request_complete.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Gaurav Jain <gaurav.jain@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>