mac80211: minstrel_ht: add flag to indicate missing/inaccurate tx A-MPDU length

Some hardware (e.g. MediaTek MT7603) cannot report A-MPDU length in tx status
information. Add support for a flag to indicate that, to allow minstrel_ht
to use a fixed value in its internal calculation (which gives better results
than just defaulting to 1).

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 5d36eac..a285c2b 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2190,6 +2190,9 @@ struct ieee80211_txq {
  *	MMPDUs on station interfaces. This of course requires the driver to use
  *	TXQs to start with.
  *
+ * @IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN: Driver does not report accurate A-MPDU
+ *	length in tx status information
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2238,6 +2241,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_BUFF_MMPDU_TXQ,
 	IEEE80211_HW_SUPPORTS_VHT_EXT_NSS_BW,
 	IEEE80211_HW_STA_MMPDU_TXQ,
+	IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS