edac: Move edac main structs to include/linux/edac.h

As we'll need to use those structs for trace functions, they should
be on a more public place. So, move struct mem_ctl_info & friends
to edac.h.

No functional changes on this patch.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>