edac: Change internal representation to work with layers

Change the EDAC internal representation to work with non-csrow
based memory controllers.

There are lots of those memory controllers nowadays, and more
are coming. So, the EDAC internal representation needs to be
changed, in order to work with those memory controllers, while
preserving backward compatibility with the old ones.

The edac core was written with the idea that memory controllers
are able to directly access csrows.

This is not true for FB-DIMM and RAMBUS memory controllers.

Also, some recent advanced memory controllers don't present a per-csrows
view. Instead, they view memories as DIMMs, instead of ranks.

So, change the allocation and error report routines to allow
them to work with all types of architectures.

This will allow the removal of several hacks with FB-DIMM and RAMBUS
memory controllers.

Also, several tests were done on different platforms using different
x86 drivers.

TODO: a multi-rank DIMMs are currently represented by multiple DIMM
entries in struct dimm_info. That means that changing a label for one
rank won't change the same label for the other ranks at the same DIMM.
This bug is present since the beginning of the EDAC, so it is not a big
deal. However, on several drivers, it is possible to fix this issue, but
it should be a per-driver fix, as the csrow => DIMM arrangement may not
be equal for all. So, don't try to fix it here yet.

I tried to make this patch as short as possible, preceding it with
several other patches that simplified the logic here. Yet, as the
internal API changes, all drivers need changes. The changes are
generally bigger in the drivers for FB-DIMMs.

Cc: Aristeu Rozanski <arozansk@redhat.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Mark Gross <mark.gross@intel.com>
Cc: Jason Uhlenkott <juhlenko@akamai.com>
Cc: Tim Small <tim@buttersideup.com>
Cc: Ranganathan Desikan <ravi@jetztechnologies.com>
Cc: "Arvind R." <arvino55@gmail.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Egor Martovetsky <egor@pasemi.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hitoshi Mitake <h.mitake@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Niklas Söderlund" <niklas.soderlund@ericsson.com>
Cc: Shaohui Xie <Shaohui.Xie@freescale.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>