[SK_BUFF]: Introduce skb_copy_from_linear_data{_offset}

To clearly state the intent of copying from 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@redhat.com>
diff --git a/drivers/net/ni65.c b/drivers/net/ni65.c
index 782201d..3818edf 100644
--- a/drivers/net/ni65.c
+++ b/drivers/net/ni65.c
@@ -1176,8 +1176,9 @@
 		if( (unsigned long) (skb->data + skb->len) > 0x1000000) {
 #endif
 
-			memcpy((char *) p->tmdbounce[p->tmdbouncenum] ,(char *)skb->data,
-							 (skb->len > T_BUF_SIZE) ? T_BUF_SIZE : skb->len);
+			skb_copy_from_linear_data(skb, p->tmdbounce[p->tmdbouncenum],
+				      skb->len > T_BUF_SIZE ? T_BUF_SIZE :
+							      skb->len);
 			if (len > skb->len)
 				memset((char *)p->tmdbounce[p->tmdbouncenum]+skb->len, 0, len-skb->len);
 			dev_kfree_skb (skb);