amd64_edac: fix K8 intlv_sel check

The check when DRAM interleaving is enabled should be done against the
pvt->dram_IntlvSel field and not against the ->dram_limit.

Simplify first loop and fixup printk formatting while at it.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>