mac80211: provide per-TID RX/TX MSDU counters

Implement the new counters cfg80211 can now advertise to userspace.
The TX code is in the sequence number handler, which is a bit odd,
but that place already knows the TID and frame type, so it was
easiest and least impact there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 058686a..da7f352 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -815,6 +815,8 @@
 		/* for pure STA mode without beacons, we can do it */
 		hdr->seq_ctrl = cpu_to_le16(tx->sdata->sequence_number);
 		tx->sdata->sequence_number += 0x10;
+		if (tx->sta)
+			tx->sta->tx_msdu[IEEE80211_NUM_TIDS]++;
 		return TX_CONTINUE;
 	}
 
@@ -831,6 +833,7 @@
 	qc = ieee80211_get_qos_ctl(hdr);
 	tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
 	seq = &tx->sta->tid_seq[tid];
+	tx->sta->tx_msdu[tid]++;
 
 	hdr->seq_ctrl = cpu_to_le16(*seq);