batman-adv: Remove uses of return value of seq_printf

This function is soon going to return void so remove the
return value use.

Convert the return value to test seq_has_overflowed() instead.
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/batman-adv/gateway_client.c

@@ -592,7 +592,7 @@ static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 
 	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 
-	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
+	seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
 		   (curr_gw == gw_node ? "=>" : "  "),
 		   gw_node->orig_node->orig,
 		   router_ifinfo->bat_iv.tq_avg, router->addr,
@@ -601,6 +601,7 @@ static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
 		   gw_node->bandwidth_down % 10,
 		   gw_node->bandwidth_up / 10,
 		   gw_node->bandwidth_up % 10);
+	ret = seq_has_overflowed(seq);
 
 	if (curr_gw)
 		batadv_gw_node_free_ref(curr_gw);