85xx: Fix address map for 36-bit config of MPC8572DS

When we introduced the 36-bit config of the MPC8572DS board we had the
wrong PCI MEM bus address map.  Additionally, the change to the address
map exposes a small issue in our dummy read on the ULI bus.  We need
to use the new mapping functions to handle that read properly in the
36-bit config.

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