net: Remove casts of void *

Unnecessary casts of void * clutter the code.

These are the remainder casts after several specific
patches to remove netdev_priv and dev_priv.

Done via coccinelle script:

$ cat cast_void_pointer.cocci
@@
type T;
T *pt;
void *pv;
@@

- pt = (T *)pv;
+ pt = pv;

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>
diff --git a/net/atm/mpc.c b/net/atm/mpc.c
index 3ccca42..aa972409f 100644
--- a/net/atm/mpc.c
+++ b/net/atm/mpc.c
@@ -1005,7 +1005,7 @@
 	struct mpoa_client *mpc;
 	struct lec_priv *priv;
 
-	dev = (struct net_device *)dev_ptr;
+	dev = dev_ptr;
 
 	if (!net_eq(dev_net(dev), &init_net))
 		return NOTIFY_DONE;