this function is used on serial output of tyan s8226 Change-Id: I5f7fa535b922b224e381886f1bea64623fa549ef Signed-off-by: Siyuan Wang <SiYuan.Wang@amd.com> Signed-off-by: Siyuan Wang <wangsiyuanbuaa@gmail.com> Reviewed-on: http://review.coreboot.org/1494 Tested-by: build bot (Jenkins) Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>