crypto: hisilicon/hpre - add check before gx modulo p

mainline inclusion
from mainline-master
commit 9612581f
category: feature
bugzilla: 173981
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9612581fc10919ef70aae1fa4dcf6e20d85a14a7



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The result of gx modulo p is zero if gx is equal to p, so return
error immediately if gx is equal to p.

Signed-off-by: Hui Tang <tanghui20@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Mingqiang Ling <lingmingqiang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>