log: Use USEC_PER_SEC instead of 1000000

Signed-off-by: Radostin Stoyanov <rstoyanov1@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

criu/log.c

@@ -51,7 +51,7 @@ static void timediff(struct timeval *from, struct timeval *to)
 		to->tv_usec -= from->tv_usec;
 	else {
 		to->tv_sec--;
-		to->tv_usec += 1000000 - from->tv_usec;
+		to->tv_usec += USEC_PER_SEC - from->tv_usec;
 	}
 }