[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/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c
index d287c57..d3e2c5f 100644
--- a/drivers/usb/atm/usbatm.c
+++ b/drivers/usb/atm/usbatm.c
@@ -396,7 +396,9 @@
 			goto out;	/* atm_charge increments rx_drop */
 		}
 
-		memcpy(skb->data, skb_tail_pointer(sarb) - pdu_length, length);
+		skb_copy_to_linear_data(skb,
+					skb_tail_pointer(sarb) - pdu_length,
+					length);
 		__skb_put(skb, length);
 
 		vdbg("%s: sending skb 0x%p, skb->len %u, skb->truesize %u",
diff --git a/drivers/usb/net/asix.c b/drivers/usb/net/asix.c
index f56e2da..d5ef97b 100644
--- a/drivers/usb/net/asix.c
+++ b/drivers/usb/net/asix.c
@@ -352,7 +352,7 @@
 	skb_push(skb, 4);
 	packet_len = (((skb->len - 4) ^ 0x0000ffff) << 16) + (skb->len - 4);
 	cpu_to_le32s(&packet_len);
-	memcpy(skb->data, &packet_len, sizeof(packet_len));
+	skb_copy_to_linear_data(skb, &packet_len, sizeof(packet_len));
 
 	if ((skb->len % 512) == 0) {
 		cpu_to_le32s(&padbytes);