net: hdlc_x25: Remove unnecessary skb_reset_network_header calls

1. In x25_xmit, skb_reset_network_header is not necessary before we call
lapb_data_request. The lapb module doesn't need skb->network_header.
So there is no need to set skb->network_header before calling
lapb_data_request.

2. In x25_data_indication (called by the lapb module after data have
been received), skb_reset_network_header is not necessary before we
call netif_rx. After we call netif_rx, the code in net/core/dev.c will
call skb_reset_network_header before handing the skb to upper layers
(in __netif_receive_skb_core, called by __netif_receive_skb_one_core,
called by __netif_receive_skb, called by process_backlog). So we don't
need to call skb_reset_network_header by ourselves.

Cc: Martin Schiller <[e-mail]>
Signed-off-by: Xie He <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/wan/hdlc_x25.c

···
 	}
 
 	skb_push(skb, 1);
-	skb_reset_network_header(skb);
 
 	ptr  = skb->data;
 	*ptr = X25_IFACE_DATA;
···
 	switch (skb->data[0]) {
 	case X25_IFACE_DATA:	/* Data to be transmitted */
 		skb_pull(skb, 1);
-		skb_reset_network_header(skb);
 		if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 			dev_kfree_skb(skb);
 		return NETDEV_TX_OK;