Local bus binding

Segher,
Kumar said he wants an ack from you on the local bus node binding before he applies it -- can you review this patch?

http://patchwork.ozlabs.org/linuxppc/patch?id=13591

Thanks,
Scott

As discussed on IRC a bit already...

- All three "should"s should be "typically"s.
- The relevant values for "compatible" should be included.
- It is wrong to require the localbus node to be a direct child of the root node. This isn't in the binding /per se/, but both the commit message and the code do mention it.

Segher