net: amd8111e: remove redundant assignment to 'tx_index'

The variable tx_index is being initialized with a value that is never
read and re-assigned a little later, hence the initialization is redundant
and can be removed.

Cleans up clang warning:
drivers/net/ethernet/amd/amd8111e.c:652:6: warning: Value stored to
'tx_index' during its initialization is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/amd8111e.c

@@ -649,7 +649,7 @@ static void amd8111e_free_ring(struct amd8111e_priv *lp)
 static int amd8111e_tx(struct net_device *dev)
 {
 	struct amd8111e_priv *lp = netdev_priv(dev);
-	int tx_index = lp->tx_complete_idx & TX_RING_DR_MOD_MASK;
+	int tx_index;
 	int status;
 	/* Complete all the transmit packet */
 	while (lp->tx_complete_idx != lp->tx_idx){