can: Delete unnecessary checks before the macro call “dev_kfree_skb”

The dev_kfree_skb() function performs also input parameter validation.
Thus the test around the shown calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Acked-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/spi/hi311x.c

@@ -177,8 +177,7 @@ static void hi3110_clean(struct net_device *net)
 
 	if (priv->tx_skb || priv->tx_len)
 		net->stats.tx_errors++;
-	if (priv->tx_skb)
-		dev_kfree_skb(priv->tx_skb);
+	dev_kfree_skb(priv->tx_skb);
 	if (priv->tx_len)
 		can_free_echo_skb(priv->net, 0);
 	priv->tx_skb = NULL;

drivers/net/can/spi/mcp251x.c

@@ -264,8 +264,7 @@ static void mcp251x_clean(struct net_device *net)
 
 	if (priv->tx_skb || priv->tx_len)
 		net->stats.tx_errors++;
-	if (priv->tx_skb)
-		dev_kfree_skb(priv->tx_skb);
+	dev_kfree_skb(priv->tx_skb);
 	if (priv->tx_len)
 		can_free_echo_skb(priv->net, 0);
 	priv->tx_skb = NULL;