[SK_BUFF]: Introduce skb_copy_from_linear_data{_offset}

To clearly state the intent of copying from linear sk_buffs, _offset being a
overly long variant but interesting for the sake of saving some bytes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/drivers/net/wireless/wavelan.c b/drivers/net/wireless/wavelan.c
index 2bf77b1..1cf090d6 100644
--- a/drivers/net/wireless/wavelan.c
+++ b/drivers/net/wireless/wavelan.c
@@ -2938,7 +2938,7 @@
 	 * need to pad. Jean II */
 	if (skb->len < ETH_ZLEN) {
 		memset(data, 0, ETH_ZLEN);
-		memcpy(data, skb->data, skb->len);
+		skb_copy_from_linear_data(skb, data, skb->len);
 		/* Write packet on the card */
 		if(wv_packet_write(dev, data, ETH_ZLEN))
 			return 1;	/* We failed */