net: dsa: Move ports assignment closer to error checking

Move the assignment of ports in _dsa_register_switch() closer to where
it is checked, no functional change. Re-order declarations to be
preserve the inverted christmas tree style.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/dsa2.c

@@ -586,8 +586,8 @@ static struct device_node *dsa_get_ports(struct dsa_switch *ds,
 static int _dsa_register_switch(struct dsa_switch *ds, struct device *dev)
 {
 	struct device_node *np = dev->of_node;
-	struct device_node *ports = dsa_get_ports(ds, np);
 	struct dsa_switch_tree *dst;
+	struct device_node *ports;
 	u32 tree, index;
 	int i, err;
 
@@ -595,6 +595,7 @@ static int _dsa_register_switch(struct dsa_switch *ds, struct device *dev)
 	if (err)
 		return err;
 
+	ports = dsa_get_ports(ds, np);
 	if (IS_ERR(ports))
 		return PTR_ERR(ports);