PowerPC changes provided by Pavel Roskin.
* kern/powerpc/ieee1275/cmain.c (cmain): Don't take any arguments.
* kern/powerpc/ieee1275/crt0.S: Store r5 in grub_ieee1275_entry_fn,
don't rely on cmain() doing it.
* kern/i386/ieee1275/startup.S (_start): Store %eax in
grub_ieee1275_entry_fn, don't rely on cmain() doing it.