powerpc/86xx: Fix PCI interrupt map definition

Fix PCI interrupt map definition from 2 to 4 cells. Move
interrupt-map and interrupt-map-mask and clone interrupts
into the pcie child nodes.

Signed-off-by: Alessio Igor Bogani <alessio.bogani@elettra.eu>
Signed-off-by: Scott Wood <oss@buserror.net>