Kunpeng930 hardware supports address prefetching to improve performance
before doing tasks in SVA scenario.

This patch enables this function in device initialization by writing
hardware registers. In the process of reset, address prefetching is
disabled to avoid the failure of interaction between accelerator device
and SMMU.
Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>