cfg80211: don't put kek/kck/replay counter on the stack

There's no need to put the values on the stack, just pass a
pointer to the data in the nl80211 message. This reduces stack
usage and avoids potential issues with putting sensitive data
on the stack.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0d17ec9..c2c710c 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1980,14 +1980,12 @@
 
 /**
  * struct cfg80211_gtk_rekey_data - rekey data
- * @kek: key encryption key
- * @kck: key confirmation key
- * @replay_ctr: replay counter
+ * @kek: key encryption key (NL80211_KEK_LEN bytes)
+ * @kck: key confirmation key (NL80211_KCK_LEN bytes)
+ * @replay_ctr: replay counter (NL80211_REPLAY_CTR_LEN bytes)
  */
 struct cfg80211_gtk_rekey_data {
-	u8 kek[NL80211_KEK_LEN];
-	u8 kck[NL80211_KCK_LEN];
-	u8 replay_ctr[NL80211_REPLAY_CTR_LEN];
+	const u8 *kek, *kck, *replay_ctr;
 };
 
 /**