can: c_can: export c_can_ethtool_ops and remove c_can_set_ethtool_ops()

The function c_can_set_ethtool_ops() does one thing: populate
net_device::ethtool_ops. Instead, it is possible to directly assign
this field and remove one function call and slightly reduce the object
size. To do so, export c_can_ethtool_ops so it becomes visible to
c_can_main.c.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20220727104939.279022-3-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/c_can/c_can.h

@@ -223,7 +223,7 @@ int c_can_power_up(struct net_device *dev);
 int c_can_power_down(struct net_device *dev);
 #endif
 
-void c_can_set_ethtool_ops(struct net_device *dev);
+extern const struct ethtool_ops c_can_ethtool_ops;
 
 static inline u8 c_can_get_tx_head(const struct c_can_tx_ring *ring)
 {

drivers/net/can/c_can/c_can_ethtool.c

@@ -24,11 +24,6 @@ static void c_can_get_ringparam(struct net_device *netdev,
 	ring->tx_pending = priv->msg_obj_tx_num;
 }
 
-static const struct ethtool_ops c_can_ethtool_ops = {
+const struct ethtool_ops c_can_ethtool_ops = {
 	.get_ringparam = c_can_get_ringparam,
 };
-
-void c_can_set_ethtool_ops(struct net_device *netdev)
-{
-	netdev->ethtool_ops = &c_can_ethtool_ops;
-}

drivers/net/can/c_can/c_can_main.c

@@ -1364,7 +1364,7 @@ int register_c_can_dev(struct net_device *dev)
 
 	dev->flags |= IFF_ECHO;	/* we support local echo */
 	dev->netdev_ops = &c_can_netdev_ops;
-	c_can_set_ethtool_ops(dev);
+	dev->ethtool_ops = &c_can_ethtool_ops;
 
 	return register_candev(dev);
 }