mac80211: move TX station pointer and restructure TX

Remove the control.sta pointer from ieee80211_tx_info to free up
sufficient space in the TX skb control buffer for the upcoming
Transmit Power Control (TPC).
Instead, the pointer is now on the stack in a new control struct
that is passed as a function parameter to the drivers' tx method.

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: Alina Friedrichsen <x-alina@gmx.net>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[reworded commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/adm8211.c b/drivers/net/wireless/adm8211.c
index 689a71c..154a496 100644
--- a/drivers/net/wireless/adm8211.c
+++ b/drivers/net/wireless/adm8211.c
@@ -1661,7 +1661,9 @@
 }
 
 /* Put adm8211_tx_hdr on skb and transmit */
-static void adm8211_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
+static void adm8211_tx(struct ieee80211_hw *dev,
+		       struct ieee80211_tx_control *control,
+		       struct sk_buff *skb)
 {
 	struct adm8211_tx_hdr *txhdr;
 	size_t payload_len, hdrlen;