net: dl2k: remove variable tx_use

Variable tx_use is just being incremented and it's never used
anywhere else. The variable and the increment are redundant so
remove it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20221024143501.2163720-1-colin.i.king@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/dlink/dl2k.c

@@ -814,7 +814,6 @@ rio_free_tx (struct net_device *dev, int irq)
 {
 	struct netdev_private *np = netdev_priv(dev);
 	int entry = np->old_tx % TX_RING_SIZE;
-	int tx_use = 0;
 	unsigned long flag = 0;
 
 	if (irq)
@@ -839,7 +838,6 @@ rio_free_tx (struct net_device *dev, int irq)
 
 		np->tx_skbuff[entry] = NULL;
 		entry = (entry + 1) % TX_RING_SIZE;
-		tx_use++;
 	}
 	if (irq)
 		spin_unlock(&np->tx_lock);