amd64_edac: add support for systems with different types of memory modules

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2048800

These two patches are the missing pieces in order to support AMD systems with
different types of memory (e.g. DDR4/DDR5 mixed systems)

Signed-off-by: Aristeu Rozanski arozansk@redhat.com