minstrel_ht: remove unnecessary NULL check in minstrel_ht_update_caps

If sta is NULL, we will have problems long before we get here...
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Cc: Felix Fietkau <nbd@openwrt.org>

net/mac80211/rc80211_minstrel_ht.c

@@ -636,7 +636,7 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
 	int i;
 
 	/* fall back to the old minstrel for legacy stations */
-	if (sta && !sta->ht_cap.ht_supported) {
+	if (!sta->ht_cap.ht_supported) {
 		msp->is_ht = false;
 		memset(&msp->legacy, 0, sizeof(msp->legacy));
 		msp->legacy.r = msp->ratelist;