iommu/riscv: Advertise Svpbmt support to generic page table

iommu/riscv: Advertise Svpbmt support to generic page table

The RISC-V IOMMU can optionally support Svpbmt page-based memory types
in its page table format. When present,the generic page table code can
use this capability to encode memory attributes (e.g. MMIO vs normal
memory) in PTEs.

Signed-off-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>