Revert "mac80211: add pointer for driver use to key"

This reverts commit f9a060f4.

No driver has turned up needing this functionality, and I've just
implemented the functionality I wanted this for in a different
way. Thus, remove it again, until somebody shows up with a need
for having it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1497,10 +1497,8 @@ enum ieee80211_key_flags {
  * 	- Temporal Authenticator Rx MIC Key (64 bits)
  * @icv_len: The ICV length for this key type
  * @iv_len: The IV length for this key type
- * @drv_priv: pointer for driver use
  */
 struct ieee80211_key_conf {
-	void *drv_priv;
 	atomic64_t tx_pn;
 	u32 cipher;
 	u8 icv_len;