[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>

drivers/net/irda/ali-ircc.c

@@ -1923,7 +1923,7 @@ static int  ali_ircc_dma_receive_complete(struct ali_ircc_cb *self)
 			
 			/* Copy frame without CRC, CRC is removed by hardware*/
 			skb_put(skb, len);
-			memcpy(skb->data, self->rx_buff.data, len);
+			skb_copy_to_linear_data(skb, self->rx_buff.data, len);
 
 			/* Move to next frame */
 			self->rx_buff.data += len;