EDAC/i5000: Mark as BROKEN

i5000_edac supports very old hardware which isn't available and it's
been broken for single/dual channel for many years without anyone
noticing. Marking as BROKEN.

Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220921181009.oxytvicy6sry6it7@redhat.com