net: add netlink_ext_ack argument to rtnl_link_ops.slave_changelink

Add support for extended error reporting.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 7136588..658a489 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2631,7 +2631,8 @@
 					return -EOPNOTSUPP;
 
 				err = m_ops->slave_changelink(master_dev, dev,
-							      tb, slave_data);
+							      tb, slave_data,
+							      extack);
 				if (err < 0)
 					return err;
 				status |= DO_SETLINK_NOTIFY;