mac80211: fix update_tkip_key() documentation about the context

Johannes noticed that I had incorrectly documented the context of
update_tkip_key() driver operation. It must be atomic because all
RX code is run inside rcu critical section.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

@@ -1489,7 +1489,7 @@ enum ieee80211_ampdu_mlme_action {
  * @update_tkip_key: See the section "Hardware crypto acceleration"
  * 	This callback will be called in the context of Rx. Called for drivers
  * 	which set IEEE80211_KEY_FLAG_TKIP_REQ_RX_P1_KEY.
- *	The callback can sleep.
+ *	The callback must be atomic.
  *
  * @hw_scan: Ask the hardware to service the scan request, no need to start
  *	the scan state machine in stack. The scan must honour the channel

net/mac80211/driver-ops.h

@@ -144,8 +144,6 @@ static inline void drv_update_tkip_key(struct ieee80211_local *local,
 {
 	struct ieee80211_sta *ista = NULL;
 
-	might_sleep();
-
 	if (sta)
 		ista = &sta->sta;