mac80211: use capped prob when computing throughputs

Commit 3e8b1eb2 "mac80211/minstrel_ht: improve rate selection stability"
introduced a local capped prob in minstrel_ht_calc_tp but omitted to use
it to compute the per rate throughput.
Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rc80211_minstrel_ht.c

@@ -226,7 +226,7 @@ minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
 		nsecs = 1000 * mi->overhead / MINSTREL_TRUNC(mi->avg_ampdu_len);
 
 	nsecs += minstrel_mcs_groups[group].duration[rate];
-	tp = 1000000 * ((mr->probability * 1000) / nsecs);
+	tp = 1000000 * ((prob * 1000) / nsecs);
 
 	mr->cur_tp = MINSTREL_TRUNC(tp);
 }