[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/eepro100.c b/drivers/net/eepro100.c
index db658bc..6c267c3 100644
--- a/drivers/net/eepro100.c
+++ b/drivers/net/eepro100.c
@@ -1804,8 +1804,9 @@
 				eth_copy_and_sum(skb, sp->rx_skbuff[entry]->data, pkt_len, 0);
 				skb_put(skb, pkt_len);
 #else
-				memcpy(skb_put(skb, pkt_len), sp->rx_skbuff[entry]->data,
-					   pkt_len);
+				skb_copy_from_linear_data(sp->rx_skbuff[entry],
+							  skb_put(skb, pkt_len),
+							  pkt_len);
 #endif
 				pci_dma_sync_single_for_device(sp->pdev, sp->rx_ring_dma[entry],
 											   sizeof(struct RxFD) + pkt_len,