ensure timekeeping_forward_now.constprop.8 and
timekeeping_forward_now.constprop.9 are correlated.

diff -Nupr src.orig/kernel/time/timekeeping.c src/kernel/time/timekeeping.c
--- src.orig/kernel/time/timekeeping.c	2017-11-17 15:58:51.500211972 -0500
+++ src/kernel/time/timekeeping.c	2017-11-17 15:59:03.810211972 -0500
@@ -1206,6 +1206,9 @@ void do_gettimeofday(struct timeval *tv)
 {
 	struct timespec64 now;
 
+	if (!tv)
+		return;
+
 	getnstimeofday64(&now);
 	tv->tv_sec = now.tv_sec;
 	tv->tv_usec = now.tv_nsec/1000;