crypto: hisilicon/hpre - support the hpre algorithm fallback

crypto: hisilicon/hpre - support the hpre algorithm fallback

When all hardware queues are busy and no shareable queue,
new processes fail to apply for queues. To avoid affecting
tasks, support fallback mechanism when hardware queues are
unavailable.

HPRE driver supports DH algorithm, limited to prime numbers up to 4K.
It supports prime numbers larger than 4K via fallback mechanism.

Fixes: 05e7b906aa7c ("crypto: hisilicon/hpre - add 'ECDH' algorithm")
Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>