i7core_edac: properly terminate pci_dev_table

At pci_xeon_fixup(), it waits for a null-terminated table, while at
i7core_get_all_devices, it just do a for 0..ARRAY_SIZE. As other tables
are zero-terminated, change it to be terminate with 0 as well, and fixes
a bug where it may be running out of the table elements.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>