RFC: proposed arch/powerpc directory structure

[Olaf Hering]

 On Wed, Aug 10, Becky Bruce wrote:

> 	boot/
> 		- Pre-kernel execution shims and pre-passes.
> 		- Convert firmware reprensentations (bi_recs, OF Dev-Trees,
> 		 bootx,bd_t) to flat-dev-trees.
> 		- Includes merged files from arch/ppc*/boot/ trees, plus
> 		prom_init.c from arch/ppc64/kernel.

This should live outside the kernel source, in a $mkzimage project.