85xx: Fix bug in device tree setup in 36-bit physical confg

85xx: Fix bug in device tree setup in 36-bit physical confg

In the 36-bit physical config for MPC8572DS when need the start address
of memory and it size to be kept in phys_*_t instead of a ulong since
we support >4G of memory in the config and ulong cant represent that.
Otherwise we end up seeing the memory node in the device tree reporting
back we have memory starting @ 0 and of size 0.

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