staging: wilc1000: use reset to set mac header

Since offset is zero, it's not necessary to use set function. Reset
function is straightforward, and will remove the unnecessary add
operation in set function.
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/staging/wilc1000/linux_mon.c

@@ -111,7 +111,7 @@ void WILC_WFI_monitor_rx(u8 *buff, u32 size)
 	}
 
 	skb->dev = wilc_wfi_mon;
-	skb_set_mac_header(skb, 0);
+	skb_reset_mac_header(skb);
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
 	skb->pkt_type = PACKET_OTHERHOST;
 	skb->protocol = htons(ETH_P_802_2);
@@ -215,7 +215,7 @@ static netdev_tx_t WILC_WFI_mon_xmit(struct sk_buff *skb,
 		cb_hdr->tx_flags = 0x0004;
 
 		skb2->dev = wilc_wfi_mon;
-		skb_set_mac_header(skb2, 0);
+		skb_reset_mac_header(skb2);
 		skb2->ip_summed = CHECKSUM_UNNECESSARY;
 		skb2->pkt_type = PACKET_OTHERHOST;
 		skb2->protocol = htons(ETH_P_802_2);