networking: make skb_put & friends return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions (skb_put, __skb_put and pskb_put) return void *
and remove all the casts across the tree, adding a (u8 *) cast only
where the unsigned char pointer was used directly, all done with the
following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_put, __skb_put };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_put, __skb_put };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

which actually doesn't cover pskb_put since there are only three
users overall.

A handful of stragglers were converted manually, notably a macro in
drivers/isdn/i4l/isdn_bsdcomp.c and, oddly enough, one of the many
instances in net/bluetooth/hci_sock.c. In the former file, I also
had to fix one whitespace problem spatch introduced.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index 2c6de76..15fb284 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -1175,7 +1175,7 @@ static void mk_tid_release(struct sk_buff *skb, unsigned int chan,
 	struct cpl_tid_release *req;
 
 	set_wr_txq(skb, CPL_PRIORITY_SETUP, chan);
-	req = (struct cpl_tid_release *)__skb_put(skb, sizeof(*req));
+	req = __skb_put(skb, sizeof(*req));
 	INIT_TP_WR(req, tid);
 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_TID_RELEASE, tid));
 }
@@ -1359,7 +1359,7 @@ int cxgb4_create_server(const struct net_device *dev, unsigned int stid,
 		return -ENOMEM;
 
 	adap = netdev2adap(dev);
-	req = (struct cpl_pass_open_req *)__skb_put(skb, sizeof(*req));
+	req = __skb_put(skb, sizeof(*req));
 	INIT_TP_WR(req, 0);
 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_PASS_OPEN_REQ, stid));
 	req->local_port = sport;
@@ -1400,7 +1400,7 @@ int cxgb4_create_server6(const struct net_device *dev, unsigned int stid,
 		return -ENOMEM;
 
 	adap = netdev2adap(dev);
-	req = (struct cpl_pass_open_req6 *)__skb_put(skb, sizeof(*req));
+	req = __skb_put(skb, sizeof(*req));
 	INIT_TP_WR(req, 0);
 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_PASS_OPEN_REQ6, stid));
 	req->local_port = sport;
@@ -1432,7 +1432,7 @@ int cxgb4_remove_server(const struct net_device *dev, unsigned int stid,
 	if (!skb)
 		return -ENOMEM;
 
-	req = (struct cpl_close_listsvr_req *)__skb_put(skb, sizeof(*req));
+	req = __skb_put(skb, sizeof(*req));
 	INIT_TP_WR(req, 0);
 	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_CLOSE_LISTSRV_REQ, stid));
 	req->reply_ctrl = htons(NO_REPLY_V(0) | (ipv6 ? LISTSVR_IPV6_V(1) :