switchdev: don't use anonymous union on switchdev attr/obj structs

Older gcc versions (e.g.  gcc version 4.4.6) don't like anonymous unions
which was causing build issues on the newly added switchdev attr/obj
structs.  Fix this by using named union on structs.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Reported-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/net-sysfs.c

@@ -465,8 +465,8 @@ static ssize_t phys_switch_id_show(struct device *dev,
 
 		ret = switchdev_port_attr_get(netdev, &attr);
 		if (!ret)
-			ret = sprintf(buf, "%*phN\n", attr.ppid.id_len,
-				      attr.ppid.id);
+			ret = sprintf(buf, "%*phN\n", attr.u.ppid.id_len,
+				      attr.u.ppid.id);
 	}
 	rtnl_unlock();