mac80211: Update comments on radiotap MCS index

mac80211 now supports passing MCS index to radiotap, so update the
comments regarding this

Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

@@ -142,11 +142,8 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 	/* IEEE80211_RADIOTAP_RATE */
 	if (status->flag & RX_FLAG_HT) {
 		/*
-		 * TODO: add following information into radiotap header once
-		 * suitable fields are defined for it:
-		 * - MCS index (status->rate_idx)
-		 * - HT40 (status->flag & RX_FLAG_40MHZ)
-		 * - short-GI (status->flag & RX_FLAG_SHORT_GI)
+		 * MCS information is a separate field in radiotap,
+		 * added below.
 		 */
 		*pos = 0;
 	} else {