iommupt: Directly call iommupt's unmap_range()

iommupt: Directly call iommupt's unmap_range()

The common algorithm in iommupt does not require the iommu_pgsize()
calculations, it can directly unmap any arbitrary range. Add a new function
pointer to directly call an iommupt unmap_range op and make
__iommu_unmap() call it directly.

Gives about a 5% gain on single page unmappings.

The function pointer is run through pt_iommu_ops instead of
iommu_domain_ops to discourage using it outside iommupt. All drivers with
their own page tables should continue to use the simplified
map/unmap_pages() style interfaces.

Reviewed-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>