iwlegacy: 4965-rs: remove unnecessary null check for sta and lq_sta

both sta and lq_sta are guaranteed to be not null in the calling
function so we don't need to check them here.
Signed-off-by: Greg Dietsche <Gregory.Dietsche@cuw.edu>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>

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

@@ -1793,9 +1793,6 @@ il4965_rs_rate_scale_perform(struct il_priv *il, struct sk_buff *skb,
 	    (info->flags & IEEE80211_TX_CTL_NO_ACK))
 		return;
 
-	if (!sta || !lq_sta)
-		return;
-
 	lq_sta->supp_rates = sta->supp_rates[lq_sta->band];
 
 	tid = il4965_rs_tl_add_packet(lq_sta, hdr);