[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/pci-skeleton.c b/drivers/net/pci-skeleton.c
index 099972c..df8998b 100644
--- a/drivers/net/pci-skeleton.c
+++ b/drivers/net/pci-skeleton.c
@@ -1344,7 +1344,7 @@
 
 	tp->tx_info[entry].skb = skb;
 	/* tp->tx_info[entry].mapping = 0; */
-	memcpy (tp->tx_buf[entry], skb->data, skb->len);
+	skb_copy_from_linear_data(skb, tp->tx_buf[entry], skb->len);
 
 	/* Note: the chip doesn't have auto-pad! */
 	NETDRV_W32 (TxStatus0 + (entry * sizeof(u32)),