cfg80211: constify more pointers in the cfg80211 API

This also propagates through the drivers.

The orinoco driver uses the cfg80211 API structs for internal
bookkeeping, and so needs a (void *) cast that removes the
const - but that's OK because it allocates those pointers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 8c61d5c..fa61ac9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -476,7 +476,8 @@
 EXPORT_SYMBOL(ieee80211_data_to_8023);
 
 int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr,
-			     enum nl80211_iftype iftype, u8 *bssid, bool qos)
+			     enum nl80211_iftype iftype,
+			     const u8 *bssid, bool qos)
 {
 	struct ieee80211_hdr hdr;
 	u16 hdrlen, ethertype;