iommu/amd: Define per-IOMMU iopf_queue

iommu/amd: Define per-IOMMU iopf_queue

AMD IOMMU hardware supports PCI Peripheral Paging Request (PPR) using
a PPR log, which is a circular buffer containing requests from downstream
end-point devices.

There is one PPR log per IOMMU instance. Therefore, allocate an iopf_queue
per IOMMU instance during driver initialization, and free the queue during
driver deinitialization.

Also rename enable_iommus_v2() -> enable_iommus_ppr() to reflect its
usage. And add amd_iommu_gt_ppr_supported() check before enabling PPR
log.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240418103400.6229-10-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>