[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/irda/w83977af_ir.c b/drivers/net/irda/w83977af_ir.c
index 0d4a686..5182e80 100644
--- a/drivers/net/irda/w83977af_ir.c
+++ b/drivers/net/irda/w83977af_ir.c
@@ -908,10 +908,14 @@
 			/* Copy frame without CRC */
 			if (self->io.speed < 4000000) {
 				skb_put(skb, len-2);
-				memcpy(skb->data, self->rx_buff.data, len-2);
+				skb_copy_to_linear_data(skb,
+							self->rx_buff.data,
+							len - 2);
 			} else {
 				skb_put(skb, len-4);
-				memcpy(skb->data, self->rx_buff.data, len-4);
+				skb_copy_to_linear_data(skb,
+							self->rx_buff.data,
+							len - 4);
 			}
 
 			/* Move to next frame */