amd64_edac: fix a wrong goto clause in amd64_edac.c

In amd64_edac_init(void) in amd64_edac.c, cache_k8_northbridges() is
called before pci_register_driver. If it fails, should exit with err
directly.

Signed-off-by: Li Hong <lihong.hi@gmail.com>
Acked-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>