EDAC: Don't add devices under /sys/bus/edac

Nobody(*) uses them. Dropping this will allow us to make the total
number of memory controllers configurable (as we won't have to worry
about duplicated device names under this directory).

(*) https://lkml.kernel.org/r/20180927221054.580220e5@coco.lan



Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
CC: Aristeu Rozanski Filho <arozansk@redhat.com>
CC: Greg KH <gregkh@linuxfoundation.org>
CC: Justin Ernst <justin.ernst@hpe.com>
CC: Mauro Carvalho Chehab <mchehab@kernel.org>
CC: Russ Anderson <rja@hpe.com>
CC: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20181001224313.GA9487@agluck-desk