powerpc/pseries: Remove IOMMU API support for non-LPAR systems

powerpc/pseries: Remove IOMMU API support for non-LPAR systems

BugLink: https://bugs.launchpad.net/bugs/1819989
The pci_dma_bus_setup_pSeries and pci_dma_dev_setup_pSeries hooks are
registered for the pseries platform which does not have FW_FEATURE_LPAR;
these would be pre-powernv platforms which we never supported PCI pass
through for anyway so remove it.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit c409c6316166993163e29312aeaaf1c0c300a04a)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>