edac: Get rid of the old kobj's from the edac mc code

Now that al users for the old kobj raw access are gone,
we can get rid of the legacy kobj-based structures and
data.

Reviewed-by: Aristeu Rozanski <arozansk@redhat.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>