This is the third & hopefully final version of the monster cleanup
patch. It does significant cleanups of the early boot code of the
ppc64 kernel, and begins the long process of cleaning up & splitting
properly the platform support.

It completely reworks the interface between the early code that is
run in the firmware context (prom_init) and the rest of the kernel,
in such a way that will make kexec or static device-tree for embedded
people possible. The early init code can eventually be moved to a
separate link entity, it no longer touches any of the kernel globals,
everything is passed via a single blob of data in memory containing
a flattened version of the device-tree and a memory reserve map.

While doing it, I also cut the ties between pSeries and Powermac. Now,
the kernel config provides a choice between legacy iSeries and
"multiplatform". The later is a set of various supported platform,
each of them beeing a boolean switch, currently defined beeing pSeries
and PowerMac. You can enable both or just one of them. CONFIG_PPC_PSERIES
is now specifically set for IBM pSeries support, you can build a PowerMac
kernel without pSeries support if you which.
The main goal here is to simplify addition of new platform types.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>