mac80211: add a flag to indicate CCK support for HT clients

brcm80211 cannot handle sending frames with CCK rates as part of an
A-MPDU session. Other drivers may have issues too. Set the flag in all
drivers that have been tested with CCK rates.

This fixes a reported brcmsmac regression introduced in
commit ef47a5e4f1aaf1d0e2e6875e34b2c9595897bef6
"mac80211/minstrel_ht: fix cck rate sampling"

Cc: stable@vger.kernel.org # 3.10
Reported-by: Tom Gundersen <teg@jklm.no>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index f5aed96..f3bbea1 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -828,6 +828,9 @@
 	if (sband->band != IEEE80211_BAND_2GHZ)
 		return;
 
+	if (!(mp->hw->flags & IEEE80211_HW_SUPPORTS_HT_CCK_RATES))
+		return;
+
 	mi->cck_supported = 0;
 	mi->cck_supported_short = 0;
 	for (i = 0; i < 4; i++) {