amd/agesa/f15/Proc/Common/S3SaveState.c: Sync with f15tn

Change-Id: If46079c1affc7d74767c4215467fd6754b24f20c
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7576
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)