[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/atari_bionet.c b/drivers/net/atari_bionet.c
index f52e7f2..13dbed3 100644
--- a/drivers/net/atari_bionet.c
+++ b/drivers/net/atari_bionet.c
@@ -453,7 +453,8 @@
 		stdma_lock(bionet_intr, NULL);
 		local_irq_restore(flags);
 		if( !STRAM_ADDR(buf+length-1) ) {
-			memcpy(nic_packet->buffer, skb->data, length);
+			skb_copy_from_linear_data(skb, nic_packet->buffer,
+						  length);
 			buf = (unsigned long)&((struct nic_pkt_s *)phys_nic_packet)->buffer;
 		}