iwlegacy: remove redundant pointer sta_priv

Pointer sta_priv is assigned but never read, hence it is redundant
and can be removed. Cleans up clang warning:

drivers/net/wireless/intel/iwlegacy/4965-rs.c:2163:2: warning: Value
stored to 'sta_priv' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intel/iwlegacy/4965-rs.c

@@ -2154,13 +2154,11 @@ il4965_rs_initialize_lq(struct il_priv *il, struct ieee80211_conf *conf,
 	u8 use_green;
 	u8 active_tbl = 0;
 	u8 valid_tx_ant;
-	struct il_station_priv *sta_priv;
 
 	if (!sta || !lq_sta)
 		return;
 
 	use_green = il4965_rs_use_green(il, sta);
-	sta_priv = (void *)sta->drv_priv;
 
 	i = lq_sta->last_txrate_idx;