drivers/net/wan: delete unneeded call to netdev_priv

Netdev_priv is an accessor function, and has no purpose if its result is
not used.

A simplified version of the semantic match that fixes this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@ local idexpression x; @@
-x = netdev_priv(...);
... when != x
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wan/sdla.c

@@ -1322,10 +1322,6 @@ NOTE:  This is rather a useless action right now, as the
 
 static int sdla_change_mtu(struct net_device *dev, int new_mtu)
 {
-	struct frad_local *flp;
-
-	flp = netdev_priv(dev);
-
 	if (netif_running(dev))
 		return -EBUSY;