batman-adv: unset the TT_CLIENT_PENDING flag if the new local entry already exists

When trying to add a new tt_local_entry, if such entry already exists, we have
to ensure that the TT_CLIENT_PENDING flag is not set, otherwise the entry will
be deleted soon.
Reported-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

net/batman-adv/translation-table.c

@@ -206,6 +206,8 @@ void tt_local_add(struct net_device *soft_iface, const uint8_t *addr,
 
 	if (tt_local_entry) {
 		tt_local_entry->last_seen = jiffies;
+		/* possibly unset the TT_CLIENT_PENDING flag */
+		tt_local_entry->common.flags &= ~TT_CLIENT_PENDING;
 		goto out;
 	}