[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/tulip/xircom_cb.c b/drivers/net/tulip/xircom_cb.c
index 1fe3734..985a181 100644
--- a/drivers/net/tulip/xircom_cb.c
+++ b/drivers/net/tulip/xircom_cb.c
@@ -411,9 +411,9 @@
 			   sometimes sends more than you ask it to. */
 
 			memset(&card->tx_buffer[bufferoffsets[desc]/4],0,1536);
-			memcpy(&(card->tx_buffer[bufferoffsets[desc]/4]),skb->data,skb->len);
-
-
+			skb_copy_from_linear_data(skb,
+				  &(card->tx_buffer[bufferoffsets[desc] / 4]),
+						  skb->len);
 			/* FIXME: The specification tells us that the length we send HAS to be a multiple of
 			   4 bytes. */