crypto: hisilicon - fix large sgl memory allocation problem when disable smmu

When disabling SMMU, it may fail to allocate large continuous memory. This
patch fixes this by allocating memory as blocks.

Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Shukun Tan <tanshukun1@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>