mac80211: remove hw.conf.channel usage where possible

Removes hw.conf.channel usage from the following functions:
 * ieee80211_mandatory_rates
 * ieee80211_sta_get_rates
 * ieee80211_frame_duration
 * ieee80211_rts_duration
 * ieee80211_ctstoself_duration

This is in preparation for multi-channel operation.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index b39dda5..79633ae 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -334,14 +334,15 @@
 
 
 static void
-calc_rate_durations(struct ieee80211_local *local, struct minstrel_rate *d,
+calc_rate_durations(enum ieee80211_band band,
+		    struct minstrel_rate *d,
 		    struct ieee80211_rate *rate)
 {
 	int erp = !!(rate->flags & IEEE80211_RATE_ERP_G);
 
-	d->perfect_tx_time = ieee80211_frame_duration(local, 1200,
+	d->perfect_tx_time = ieee80211_frame_duration(band, 1200,
 			rate->bitrate, erp, 1);
-	d->ack_time = ieee80211_frame_duration(local, 10,
+	d->ack_time = ieee80211_frame_duration(band, 10,
 			rate->bitrate, erp, 1);
 }
 
@@ -379,14 +380,14 @@
 {
 	struct minstrel_sta_info *mi = priv_sta;
 	struct minstrel_priv *mp = priv;
-	struct ieee80211_local *local = hw_to_local(mp->hw);
 	struct ieee80211_rate *ctl_rate;
 	unsigned int i, n = 0;
 	unsigned int t_slot = 9; /* FIXME: get real slot time */
 
 	mi->lowest_rix = rate_lowest_index(sband, sta);
 	ctl_rate = &sband->bitrates[mi->lowest_rix];
-	mi->sp_ack_dur = ieee80211_frame_duration(local, 10, ctl_rate->bitrate,
+	mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10,
+				ctl_rate->bitrate,
 				!!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1);
 
 	for (i = 0; i < sband->n_bitrates; i++) {
@@ -402,7 +403,7 @@
 
 		mr->rix = i;
 		mr->bitrate = sband->bitrates[i].bitrate / 5;
-		calc_rate_durations(local, mr, &sband->bitrates[i]);
+		calc_rate_durations(sband->band, mr, &sband->bitrates[i]);
 
 		/* calculate maximum number of retransmissions before
 		 * fallback (based on maximum segment size) */