edac: Create a dimm struct and move the labels into it

The way a DIMM is currently represented implies that they're
linked into a per-csrow struct. However, some drivers don't see
csrows, as they're ridden behind some chip like the AMB's
on FBDIMM's, for example.

This forced drivers to fake^Wvirtualize a csrow struct, and to create
a mess under csrow/channel original's concept.

Move the DIMM labels into a per-DIMM struct, and add there
the real location of the socket, in terms of csrow/channel.
Latter patches will modify the location to properly represent the
memory architecture.

All other drivers will use a per-csrow type of location.
Some of those drivers will require a latter conversion, as
they also fake the csrows internally.

TODO: While this patch doesn't change the existing behavior, on
csrows-based memory controllers, a csrow/channel pair points to a memory
rank. There's a known bug at the EDAC core that allows having different
labels for the same DIMM, if it has more than one rank. A latter patch
is need to merge the several ranks for a DIMM into the same dimm_info
struct, in order to avoid having different labels for the same DIMM.

The edac_mc_alloc() will now contain a per-dimm initialization loop that
will be changed by latter patches in order to match other types of
memory architectures.

Reviewed-by: Aristeu Rozanski <arozansk@redhat.com>
Reviewed-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Ranganathan Desikan <ravi@jetztechnologies.com>
Cc: "Arvind R." <arvino55@gmail.com>
Cc: "Niklas Söderlund" <niklas.soderlund@ericsson.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>