networking: introduce and use skb_put_data()

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

    @@
    identifier p, p2;
    expression len, skb, data;
    type t, t2;
    @@
    (
    -p = skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    |
    -p = (t)skb_put(skb, len);
    +p = skb_put_data(skb, data, len);
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, len);
    |
    -memcpy(p, data, len);
    )

    @@
    type t, t2;
    identifier p, p2;
    expression skb, data;
    @@
    t *p;
    ...
    (
    -p = skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    |
    -p = (t *)skb_put(skb, sizeof(t));
    +p = skb_put_data(skb, data, sizeof(t));
    )
    (
    p2 = (t2)p;
    -memcpy(p2, data, sizeof(*p));
    |
    -memcpy(p, data, sizeof(*p));
    )

    @@
    expression skb, len, data;
    @@
    -memcpy(skb_put(skb, len), data, len);
    +skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/intersil/p54/p54spi.c

@@ -372,9 +372,9 @@ static int p54spi_rx(struct p54s_priv *priv)
 	}
 
 	if (len <= READAHEAD_SZ) {
-		memcpy(skb_put(skb, len), rx_head + 1, len);
+		skb_put_data(skb, rx_head + 1, len);
 	} else {
-		memcpy(skb_put(skb, READAHEAD_SZ), rx_head + 1, READAHEAD_SZ);
+		skb_put_data(skb, rx_head + 1, READAHEAD_SZ);
 		p54spi_spi_read(priv, SPI_ADRS_DMA_DATA,
 				skb_put(skb, len - READAHEAD_SZ),
 				len - READAHEAD_SZ);