powerpc/powernv: Move pnv_pci_ioda_setup_opal_tce_kill() around

pnv_pci_ioda_setup_opal_tce_kill() called by pnv_ioda_setup_dma()
to remap the TCE kill regiter. What's done in pnv_ioda_setup_dma()
will be covered in pcibios_setup_bridge() which is invoked on each
PCI bridge. It means we will possibly remap the TCE kill register
for multiple times and it's unnecessary.

This moves pnv_pci_ioda_setup_opal_tce_kill() to where the PHB is
initialized (pnv_pci_init_ioda_phb()) to avoid above issue.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>