This has three main parts: (1) support for the 440GP and 440GX processors,
(2) support for the "Ebony" and "Ocotea" reference boards for those processors,
and (3) support for 64-bit physical addresses.  The 440GP and 440GX are "Book E"
processors, and this introduces a CONFIG_BOOKE and some definitions that apply
to all Book E processors.

Having 64-bit physical addresses means that PTEs are now 64 bits.  The PTE pages
stay at 4kB, and the pgdir expands to 8kB.