switchdev: make struct switchdev_attr parameter const for attr_set calls

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
index eafa907..f0e820d 100644
--- a/drivers/net/ethernet/rocker/rocker.c
+++ b/drivers/net/ethernet/rocker/rocker.c
@@ -4374,7 +4374,7 @@
 }
 
 static int rocker_port_attr_set(struct net_device *dev,
-				struct switchdev_attr *attr,
+				const struct switchdev_attr *attr,
 				struct switchdev_trans *trans)
 {
 	struct rocker_port *rocker_port = netdev_priv(dev);