crypto: hisilicon/hpre - update debugfs interface parameters

Update debugfs interface parameters, and adjust the
processing logic inside the corresponding function.

Fixes: 84897415("crypto: hisilicon - Add debugfs for HPRE")
Signed-off-by: Meng Yu <yumeng18@huawei.com>
Reviewed-by: Zaibo Xu <xuzaibo@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>