net: bridge: Slightly optimize 'find_portno()'

The 'inuse' bitmap is local to this function. So we can use the
non-atomic '__set_bit()' to save a few cycles.

While at it, also remove some useless {}.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -397,10 +397,10 @@ static int find_portno(struct net_bridge *br)
 	if (!inuse)
 		return -ENOMEM;
 
-	set_bit(0, inuse);	/* zero is reserved */
-	list_for_each_entry(p, &br->port_list, list) {
-		set_bit(p->port_no, inuse);
-	}
+	__set_bit(0, inuse);	/* zero is reserved */
+	list_for_each_entry(p, &br->port_list, list)
+		__set_bit(p->port_no, inuse);
+
 	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
 	bitmap_free(inuse);