This patch introduces the conditional changes required for the three
memory models.  With [patch 1/4] there are three memory models; FLATMEM,
DISCONTIG and SPARSEMEM.  Also a new arch include file sparemem.h is
introduced for defining SPARSEMEM parameters.

Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

New version leaves the original memory map unmodified.
Also saves any granule trimmings for use by the uncached
memory allocator.

Inspired by Khalid Aziz (various traces of his patch still
remain).  Fixes to uncached_build_memmap() and sn2 testing
by Martin Hicks.

Signed-off-by: Tony Luck <tony.luck@intel.com>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!