bnxt_en: Fix zero padding of tx push data.

The arithmetic to zero pad the last 64-bit word in the push buffer is not
correct.

1. It should be pdata + length to get to the end.
2. 'pdata' is void pointer and passing it to PTR_ALIGN() will cast the
aligned pointer to void.  Pass 'end' which is u64 pointer to PTR_ALIGN()
instead so that the aligned pointer - 1 is the last 64-bit pointer to data.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -248,7 +248,8 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		tx_push1->tx_bd_cfa_meta = cpu_to_le32(vlan_tag_flags);
 		tx_push1->tx_bd_cfa_action = cpu_to_le32(cfa_action);
 
-		end = PTR_ALIGN(pdata + length + 1, 8) - 1;
+		end = pdata + length;
+		end = PTR_ALIGN(end, 8) - 1;
 		*end = 0;
 
 		skb_copy_from_linear_data(skb, pdata, len);