Return seconds when clock_gettime error

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/platform_util.c b/library/platform_util.c
index 6c65524..2b48f4f 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -183,7 +183,7 @@
 
     ret = clock_gettime(CLOCK_REALTIME, &tv);
     if (ret) {
-        return 0;
+        return time(NULL) * 1000;
     }
 
     current_ms = tv.tv_sec;