mac80211: let the driver reserve extra tailroom in beacons

Can be used to add extra IEs (such as P2P NoA) without having to
reallocate the buffer.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 22b6dd9..531785f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1613,6 +1613,9 @@
  * @extra_tx_headroom: headroom to reserve in each transmit skb
  *	for use by the driver (e.g. for transmit headers.)
  *
+ * @extra_beacon_tailroom: tailroom to reserve in each beacon tx skb.
+ *	Can be used by drivers to add extra IEs.
+ *
  * @channel_change_time: time (in microseconds) it takes to change channels.
  *
  * @max_signal: Maximum value for signal (rssi) in RX information, used
@@ -1695,6 +1698,7 @@
 	void *priv;
 	u32 flags;
 	unsigned int extra_tx_headroom;
+	unsigned int extra_beacon_tailroom;
 	int channel_change_time;
 	int vif_data_size;
 	int sta_data_size;