drivers-edac: add Cell XDR memory types

Add the definitions for the Rambus XDR memory type used by the Cell processor.
It's a pre-requisite for the followup Cell EDAC patch.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>