iommu/amd: Remove the confusing dummy iommu_flush_ops tlb ops

iommu/amd: Remove the confusing dummy iommu_flush_ops tlb ops

The iommu driver is supposed to provide these ops to its io_pgtable
implementation so that it can hook the invalidations and do the right
thing.

They are called by wrapper functions like io_pgtable_tlb_add_page() etc,
which the AMD code never calls.

Instead it directly calls the AMD IOMMU invalidation functions by casting
to the struct protection_domain. Remove it all.

Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/12-v2-831cdc4d00f3+1a315-amd_iopgtbl_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>