powerpc/powernv: Missed IOMMU table type

In function pnv_pci_ioda2_setup_dma_pe(), the IOMMU table type is
set to (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE) unconditionally.
It was just set to TCE_PCI by pnv_pci_setup_iommu_table(). So the
primary IOMMU table type (TCE_PCI) is lost. The patch fixes it.

Also, pnv_pci_setup_iommu_table() already set "tbl->it_busno" to
zero and we needn't do it again. The patch removes the redundant
assignment.

The patch also fixes similar issues in pnv_pci_ioda_setup_dma_pe().

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>