IB/ipoib: drop useless LIST_HEAD

Drop LIST_HEAD where the variable it declares is never used.

Commit 31c02e2157 ("IPoIB: Avoid using stale last_send counter
when reaping AHs") removed the uses, but not the declaration.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
@@
- LIST_HEAD(x);
  ... when != x
// </smpl>

Fixes: 31c02e2157 ("IPoIB: Avoid using stale last_send counter when reaping AHs")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/ulp/ipoib/ipoib_ib.c

@@ -669,7 +669,6 @@ static void __ipoib_reap_ah(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = ipoib_priv(dev);
 	struct ipoib_ah *ah, *tah;
-	LIST_HEAD(remove_list);
 	unsigned long flags;
 
 	netif_tx_lock_bh(dev);