mac80211: add debugfs for driver-buffered TID bitmap

Add a per-station debugfs file indicating the TIDs (as
a bitmap) that the driver has data buffered on.

Reviewed-by: Emmanuel Grumbach <[e-mail]>
Signed-off-by: Johannes Berg <[e-mail]>

net/mac80211/debugfs_sta.c

···
 	DEBUGFS_ADD_COUNTER(tx_retry_count, tx_retry_count);
 	DEBUGFS_ADD_COUNTER(wep_weak_iv_count, wep_weak_iv_count);
 
+	if (sizeof(sta->driver_buffered_tids) == sizeof(u32))
+		debugfs_create_x32("driver_buffered_tids", 0400,
+				   sta->debugfs.dir,
+				   (u32 *)&sta->driver_buffered_tids);
+	else
+		debugfs_create_x64("driver_buffered_tids", 0400,
+				   sta->debugfs.dir,
+				   (u64 *)&sta->driver_buffered_tids);
+
 	drv_sta_add_debugfs(local, sdata, &sta->sta, sta->debugfs.dir);
 }