batman-adv: convert time_after instances to has_timed_out

To increase readability the has_timed_out() functions has been introduced.
This patch converts existing time_after() calls to use this wrapper
function (if applicable).
This patch also converts all timeouts to miliseconds to be consistent.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
diff --git a/net/batman-adv/vis.c b/net/batman-adv/vis.c
index ac7e661..4f4b2a0 100644
--- a/net/batman-adv/vis.c
+++ b/net/batman-adv/vis.c
@@ -714,8 +714,7 @@
 			if (info == bat_priv->my_vis_info)
 				continue;
 
-			if (time_after(jiffies,
-				       info->first_seen + VIS_TIMEOUT * HZ)) {
+			if (has_timed_out(info->first_seen, VIS_TIMEOUT)) {
 				hlist_del(node);
 				send_list_del(info);
 				kref_put(&info->refcount, free_info);