[NET]: Wrap hard_header_parse

Wrap the hard_header_parse function to simplify next step of
header_ops conversion.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 89be662..0cdcf0d 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -47,7 +47,7 @@
 
 /* common interface routines */
 
-static int header_parse_80211(struct sk_buff *skb, unsigned char *haddr)
+static int header_parse_80211(const struct sk_buff *skb, unsigned char *haddr)
 {
 	memcpy(haddr, skb_mac_header(skb) + 10, ETH_ALEN); /* addr2 */
 	return ETH_ALEN;