wifi: iwlwifi: dvm: clean up rs_get_rate() logic

The logic here is rather convoluted - we cannot get here with
lq_sta being NULL as mac80211 will (no longer) call us like
that, and since I removed the rate_control_send_low() call in
this function there's no longer any point in setting priv_sta
to NULL either.

So the only thing that remains to check is if we have actually
initialized our lq_sta->drv pointer, and exit if we didn't in
which case we'll use the data mac80211 already set up for the
low rate usage.
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Link: https://msgid.link/20240510170500.a4cdb41825eb.Id202bcc967c32829f70ab1412f8893b6eb7f78e2@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/dvm/rs.c

@@ -2673,20 +2673,16 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta, void *priv_sta,
 	IWL_DEBUG_RATE_LIMIT(priv, "rate scale calculate new rate for skb\n");
 
 	/* Get max rate if user set max rate */
-	if (lq_sta) {
-		lq_sta->max_rate_idx = fls(txrc->rate_idx_mask) - 1;
-		if ((sband->band == NL80211_BAND_5GHZ) &&
-		    (lq_sta->max_rate_idx != -1))
-			lq_sta->max_rate_idx += IWL_FIRST_OFDM_RATE;
-		if ((lq_sta->max_rate_idx < 0) ||
-		    (lq_sta->max_rate_idx >= IWL_RATE_COUNT))
-			lq_sta->max_rate_idx = -1;
-	}
+	lq_sta->max_rate_idx = fls(txrc->rate_idx_mask) - 1;
+	if (sband->band == NL80211_BAND_5GHZ && lq_sta->max_rate_idx != -1)
+		lq_sta->max_rate_idx += IWL_FIRST_OFDM_RATE;
+	if (lq_sta->max_rate_idx < 0 || lq_sta->max_rate_idx >= IWL_RATE_COUNT)
+		lq_sta->max_rate_idx = -1;
 
-	/* Treat uninitialized rate scaling data same as non-existing. */
-	if (lq_sta && !lq_sta->drv) {
+	if (!lq_sta->drv) {
 		IWL_DEBUG_RATE(priv, "Rate scaling not initialized yet.\n");
-		priv_sta = NULL;
+		/* mac80211 already set up the data for using low rates */
+		return;
 	}
 
 	rate_idx  = lq_sta->last_txrate_idx;
@@ -2756,7 +2752,6 @@ void iwl_rs_rate_init(struct iwl_priv *priv, struct ieee80211_sta *sta, u8 sta_i
 	lq_sta = &sta_priv->lq_sta;
 	sband = hw->wiphy->bands[conf->chandef.chan->band];
 
-
 	lq_sta->lq.sta_id = sta_id;
 
 	for (j = 0; j < LQ_SIZE; j++)