mac80211: tdls: remove shadowing variable

There's no need to use another local 'sta' variable as the
original (outer scope) one isn't needed any more and has
become invalid anyway when exiting the RCU read section.

Remove the inner scope one and along with it the useless NULL
initialization.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/tdls.c

@@ -852,7 +852,6 @@ ieee80211_tdls_prep_mgmt_packet(struct wiphy *wiphy, struct net_device *dev,
 	 */
 	if ((action_code == WLAN_TDLS_TEARDOWN) &&
 	    (sdata->local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)) {
-		struct sta_info *sta = NULL;
 		bool try_resend; /* Should we keep skb for possible resend */
 
 		/* If not sending directly to peer - no point in keeping skb */