net: pktgen: use reset to set mac header

Since offset is zero, it's not necessary to use set function.
Signed-off-by: NZhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/pktgen.c

@@ -2856,7 +2856,7 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev,
 		*vlan_encapsulated_proto = htons(ETH_P_IP);
 	}
 
-	skb_set_mac_header(skb, 0);
+	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb->len);
 	iph = (struct iphdr *) skb_put(skb, sizeof(struct iphdr));
 
@@ -2983,7 +2983,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev,
 		*vlan_encapsulated_proto = htons(ETH_P_IPV6);
 	}
 
-	skb_set_mac_header(skb, 0);
+	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb->len);
 	iph = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr));