mac80211: use reset to set header pointer

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>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9127957..5690e4c 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3101,7 +3101,7 @@
 	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
 					 false);
 
-	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);