Programs using kmem to read kernel memory (ex: ktrdump) are
getting invalid address errors.
This happens because mem_valid() don't find direct mapped memory
range 0xc000...0000 in pranges.
As in pseries the kernel gets relocated to 0xc000...0000 early in
the boot phase, I thought that it would be reasonable to add
another memory region starting at the new address, with the same
However, I really don't know if this is the correct way to fix
This change is being done after MMU initialization, because
otherwise the system will panic saying 0xc000...0000 is already