net: macsec: fix rtnl locking issue

netdev_update_features() must be called with the rtnl lock taken. Not
doing so triggers a warning, as ASSERT_RTNL() is used in
__netdev_update_features(), the first function called by
netdev_update_features(). Fix this.

Fixes: c850240b6c41 ("net: macsec: report real_dev features when HW offloading is enabled")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index d403402..d0d31cb 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2641,11 +2641,12 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
 	if (ret)
 		goto rollback;
 
-	rtnl_unlock();
 	/* Force features update, since they are different for SW MACSec and
 	 * HW offloading cases.
 	 */
 	netdev_update_features(dev);
+
+	rtnl_unlock();
 	return 0;
 
 rollback: