powerpc/ioda/iommu/debugfs: Generate unique debugfs entries

The iommu_table::it_index is a LIOBN which is not initialized on PowerNV
as it is not used except IOMMU debugfs where it is used for a node name.

This initializes it_index witn a unique number to avoid warnings and
have a node for every iommu_table.

This should not cause any behavioral change without CONFIG_IOMMU_DEBUGFS.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220714080800.3712998-1-aik@ozlabs.ru

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -1609,6 +1609,7 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
 	tbl->it_ops = &pnv_ioda1_iommu_ops;
 	pe->table_group.tce32_start = tbl->it_offset << tbl->it_page_shift;
 	pe->table_group.tce32_size = tbl->it_size << tbl->it_page_shift;
+	tbl->it_index = (phb->hose->global_number << 16) | pe->pe_number;
 	if (!iommu_init_table(tbl, phb->hose->node, 0, 0))
 		panic("Failed to initialize iommu table");
 
@@ -1779,6 +1780,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
 		res_end = min(window_size, SZ_4G) >> tbl->it_page_shift;
 	}
 
+	tbl->it_index = (pe->phb->hose->global_number << 16) | pe->pe_number;
 	if (iommu_init_table(tbl, pe->phb->hose->node, res_start, res_end))
 		rc = pnv_pci_ioda2_set_window(&pe->table_group, 0, tbl);
 	else