powerpc: set ARCH_KMALLOC_MINALIGN if CONFIG_NOT_COHERENT_CACHE=y

[Dale Farnsworth]

In article <20060303200928.GA29099 at xyzzy.farnsworth.org> you write:
> Ensure that buffers returned by kmalloc do not share a cache
> line with other data when doing non-cache-coherent I/O.

Eugene Surovegin points out that ARCH_KMALLOC_MINALIGN
doesn't work as avertised.

This patch doesn't work.

Thanks,
-Dale