[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/arch/ia64/hp/sim/simeth.c b/arch/ia64/hp/sim/simeth.c
index edef008..f26077a 100644
--- a/arch/ia64/hp/sim/simeth.c
+++ b/arch/ia64/hp/sim/simeth.c
@@ -473,7 +473,7 @@
 		 * XXX Fix me
 		 * Should really do a csum+copy here
 		 */
-		memcpy(skb->data, frame, len);
+		skb_copy_to_linear_data(skb, frame, len);
 #endif
 		skb->protocol = eth_type_trans(skb, dev);