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>

net/sctp/input.c

@@ -510,8 +510,7 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
 	 * discard the packet.
 	 */
 	if (vtag == 0) {
-		chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr
-				+ sizeof(struct sctphdr));
+		chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
 		if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
 			  + sizeof(__be32) ||
 		    chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||