edac: move nr_pages to dimm struct

The number of pages is a dimm property. Move it to the dimm struct.

After this change, it is possible to add sysfs nodes for the DIMM's that
will properly represent the DIMM stick properties, including its size.

A TODO fix here is to properly represent dual-rank/quad-rank DIMMs when
the memory controller represents the memory via chip select rows.

Reviewed-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Doug Thompson <norsk5@yahoo.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: 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>