[POWERPC] Fix device tree interrupt map for Freescale ULI1575 boards

The interrupt map for the PCI PHB that had the ULI1575 was not correct
on the boards that have it.

* 8544 DS:
   - Fix interrupt mask
   - Be explicit about use of INTA for on chip peripherals

* 8572 DS/8641 HPCN:
   - Fix interrupt mask
   - Expand interrupt map for PCI slots to cover all functions
   - Be explicit about use of INTA for on chip peripherals

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>