iommu: debug-pagealloc: Track IOMMU pages

iommu: debug-pagealloc: Track IOMMU pages

Using the new calls, use an atomic refcount to track how many times
a page is mapped in any of the IOMMUs.

For unmap we need to use iova_to_phys() to get the physical address
of the pages.

We use the smallest supported page size as the granularity of tracking
per domain.
This is important as it is possible to map pages and unmap them with
larger sizes (as in map_sg()) cases.

Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>