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/net/mac80211/wpa.c b/net/mac80211/wpa.c
index cc19614..0d722ea 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -949,7 +949,7 @@ ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
 	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 		return TX_DROP;
 
-	mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
+	mmie = skb_put(skb, sizeof(*mmie));
 	mmie->element_id = WLAN_EID_MMIE;
 	mmie->length = sizeof(*mmie) - 2;
 	mmie->key_id = cpu_to_le16(key->conf.keyidx);
@@ -993,7 +993,7 @@ ieee80211_crypto_aes_cmac_256_encrypt(struct ieee80211_tx_data *tx)
 	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 		return TX_DROP;
 
-	mmie = (struct ieee80211_mmie_16 *)skb_put(skb, sizeof(*mmie));
+	mmie = skb_put(skb, sizeof(*mmie));
 	mmie->element_id = WLAN_EID_MMIE;
 	mmie->length = sizeof(*mmie) - 2;
 	mmie->key_id = cpu_to_le16(key->conf.keyidx);
@@ -1138,7 +1138,7 @@ ieee80211_crypto_aes_gmac_encrypt(struct ieee80211_tx_data *tx)
 	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
 		return TX_DROP;
 
-	mmie = (struct ieee80211_mmie_16 *)skb_put(skb, sizeof(*mmie));
+	mmie = skb_put(skb, sizeof(*mmie));
 	mmie->element_id = WLAN_EID_MMIE;
 	mmie->length = sizeof(*mmie) - 2;
 	mmie->key_id = cpu_to_le16(key->conf.keyidx);