net: qlge: use memmove instead of skb_copy_to_linear_data

gcc-8 points out that the skb_copy_to_linear_data() argument points to
the skb itself, which makes it run into a problem with overlapping
memcpy arguments:

In file included from include/linux/ip.h:20,
                 from drivers/net/ethernet/qlogic/qlge/qlge_main.c:26:
drivers/net/ethernet/qlogic/qlge/qlge_main.c: In function 'ql_realign_skb':
include/linux/skbuff.h:3378:2: error: 'memcpy' source argument is the same as destination [-Werror=restrict]
  memcpy(skb->data, from, len);

It's unclear to me what the best solution is, maybe it ought to use a
different helper that adjusts the skb data in a safe way. Simply using
memmove() here seems like the easiest workaround.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qlge/qlge_main.c

@@ -1747,8 +1747,7 @@ static void ql_realign_skb(struct sk_buff *skb, int len)
 	 */
 	skb->data -= QLGE_SB_PAD - NET_IP_ALIGN;
 	skb->tail -= QLGE_SB_PAD - NET_IP_ALIGN;
-	skb_copy_to_linear_data(skb, temp_addr,
-		(unsigned int)len);
+	memmove(skb->data, temp_addr, len);
 }
 
 /*