mac80211: remove zero-length A-MPDU subframe reporting

As there's no driver using this capability and reporting zero-length
A-MPDU subframes for radiotap monitoring, remove the capability to
free up two RX flags.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -997,9 +997,6 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  * @RX_FLAG_AMPDU_DETAILS: A-MPDU details are known, in particular the reference
  *	number (@ampdu_reference) must be populated and be a distinct number for
  *	each A-MPDU
- * @RX_FLAG_AMPDU_REPORT_ZEROLEN: driver reports 0-length subframes
- * @RX_FLAG_AMPDU_IS_ZEROLEN: This is a zero-length subframe, for
- *	monitoring purposes only
  * @RX_FLAG_AMPDU_LAST_KNOWN: last subframe is known, should be set on all
  *	subframes of a single A-MPDU
  * @RX_FLAG_AMPDU_IS_LAST: this subframe is the last subframe of the A-MPDU
@@ -1039,8 +1036,7 @@ enum mac80211_rx_flags {
 	RX_FLAG_NO_SIGNAL_VAL		= BIT(12),
 	RX_FLAG_HT_GF			= BIT(13),
 	RX_FLAG_AMPDU_DETAILS		= BIT(14),
-	RX_FLAG_AMPDU_REPORT_ZEROLEN	= BIT(15),
-	RX_FLAG_AMPDU_IS_ZEROLEN	= BIT(16),
+	/* bits 15/16 free */
 	RX_FLAG_AMPDU_LAST_KNOWN	= BIT(17),
 	RX_FLAG_AMPDU_IS_LAST		= BIT(18),
 	RX_FLAG_AMPDU_DELIM_CRC_ERROR	= BIT(19),

net/mac80211/rx.c

@@ -122,8 +122,7 @@ static inline bool should_drop_frame(struct sk_buff *skb, int present_fcs_len,
 	hdr = (void *)(skb->data + rtap_vendor_space);
 
 	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
-			    RX_FLAG_FAILED_PLCP_CRC |
-			    RX_FLAG_AMPDU_IS_ZEROLEN))
+			    RX_FLAG_FAILED_PLCP_CRC))
 		return true;
 
 	if (unlikely(skb->len < 16 + present_fcs_len + rtap_vendor_space))
@@ -391,10 +390,6 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 			cpu_to_le32(1 << IEEE80211_RADIOTAP_AMPDU_STATUS);
 		put_unaligned_le32(status->ampdu_reference, pos);
 		pos += 4;
-		if (status->flag & RX_FLAG_AMPDU_REPORT_ZEROLEN)
-			flags |= IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN;
-		if (status->flag & RX_FLAG_AMPDU_IS_ZEROLEN)
-			flags |= IEEE80211_RADIOTAP_AMPDU_IS_ZEROLEN;
 		if (status->flag & RX_FLAG_AMPDU_LAST_KNOWN)
 			flags |= IEEE80211_RADIOTAP_AMPDU_LAST_KNOWN;
 		if (status->flag & RX_FLAG_AMPDU_IS_LAST)