Cell kernel updates

Sorry for having delayed these patches so long. This should
bring the mainline kernel up-to-date with the experimental
stuff that is hosted on bsc.es. It should apply on today's
git tree and with trivial modifications also works on 2.6.16,
for those that are interested.

Apart from a number of bug fixes, the important parts in here
are:

- the hvc console driver for rtas
- spufs support for doing syscalls from an spu
- host-initiated DMA though spufs
- option to map SPU control registers into user space

Paulus, please apply and forward as appropriate.

        Arnd <><

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