cfg80211: remove unused wiphy argument from cfg80211_wext_freq()

cfg80211_wext_freq() is declared in wext-compat.h, but its
parameter struct wiphy's declaration is not included there.
As the parameter isn't used, just remove it.

Signed-off-by: Zhao, Gang <gamerh2o@gmail.com>
[remove parameter instead of changing to netdev]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/wext-sme.c

@@ -75,7 +75,7 @@ int cfg80211_mgd_wext_siwfreq(struct net_device *dev,
 	if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION))
 		return -EINVAL;
 
-	freq = cfg80211_wext_freq(wdev->wiphy, wextfreq);
+	freq = cfg80211_wext_freq(wextfreq);
 	if (freq < 0)
 		return freq;