[PATCH v2] Consolidate mm_context_t definition in mmu.h

[Paul Mackerras]

Josh Boyer writes:

> All of the platforms except PPC64 share a common mm_context_t definition.
> Defining it in mmu.h avoids duplicating it in the platform specific mmu
> header files.  We further consolidate it by having the PPC32 definition
> share the mm_context_id_t type for the id member.

Unfortunately the string of ifdefs in your consolidated version makes
my eyes water.  I'm not sure it isn't better the way it is.

Paul.