crypto: hisilicon - enable hpre device clock gating

Kunpeng930 hpre device supports dynamic clock gating. When doing tasks,
the algorithm core is opened, and when idle, the algorithm core is closed.
This patch enables hpre dynamic clock gating by writing hardware registers.

Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>