Add native memset() function on x86

Change-Id: Ia118ebe0a4b59bdcefd78895141a365170f6aed2
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/737
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)

src/arch/x86/lib/Makefile.inc

@@ -8,10 +8,12 @@ ramstage-$(CONFIG_MMCONF_SUPPORT) += pci_ops_mmconf.c
 ramstage-y += pci_ops_auto.c
 ramstage-y += exception.c
 ramstage-$(CONFIG_IOAPIC) += ioapic.c
+ramstage-y += memset.c
 ramstage-y += memcpy.c
 
 romstage-y += romstage_console.c
 romstage-y += cbfs_and_run.c
+romstage-y += memset.c
 romstage-y += memcpy.c
 
 smm-y += memcpy.c