86xx: Fix non-64-bit compilation problems.

Introducing 64-bit (36-bit) support for the MPC8641HPCN
failed to accomodate the other two 86xx boards.
Introduce definitions for CONFIG_SYS_CCSRBAR_PHYS_{LOW,HIGH}
CONFIG_SYS_CCSR_DEFAULT_DBAT{U,L} and CONFIG_SYS_CCSR_DEFAULT_IBAT{U,L}
with nominal 32-bit values.

Signed-off-by: Jon Loeliger <jdl@freescale.com>
Acked-by: Becky Bruce <becky.bruce@freescale.com>