Remove the "select PHYS_64BIT" from the Kconfig entry for the P1022DS,
so that large physical address support is a selectable option for non-CoreNet
The option is enabled in mpc85xx_[smp_]defconfig so that the default is
unchanged. However, now it can be deselected.
The P1022DS had this option defined because the default device tree for
this board uses 36-bit addresses. This had the side-effect of forcing
this option on for all boards that use mpc85xx_[smp_]defconfig. Some
users may want to disable this feature to create an optimized configuration
for boards with <= 2GB of RAM.