i7core_edac: Fix compilation on 32 bits arch

on i386:
	ERROR: "__udivdi3" [drivers/edac/i7core_edac.ko] undefined!\

In both get_sdram_scrub_rate() and set_sdram_scrub_rate()

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>