[SK_BUFF]: Introduce skb_copy_to_linear_data{_offset}

To clearly state the intent of copying to 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@ghostprotocols.net>
diff --git a/drivers/net/tokenring/smctr.c b/drivers/net/tokenring/smctr.c
index b0296d8..9bbea5c 100644
--- a/drivers/net/tokenring/smctr.c
+++ b/drivers/net/tokenring/smctr.c
@@ -3889,7 +3889,7 @@
 
                 /* Slide data into a sleek skb. */
                 skb_put(skb, skb->len);
-                memcpy(skb->data, rmf, skb->len);
+                skb_copy_to_linear_data(skb, rmf, skb->len);
 
                 /* Update Counters */
                 tp->MacStat.rx_packets++;
@@ -4475,7 +4475,7 @@
 				if (skb) {
                                 	skb_put(skb, rx_size);
 
-                                	memcpy(skb->data, pbuff, rx_size);
+					skb_copy_to_linear_data(skb, pbuff, rx_size);
 
                                 	/* Update Counters */
                                 	tp->MacStat.rx_packets++;