mac80211: fix memory leak

My recent change here introduced a possible memory leak if the
driver registers an invalid cipher schemes. This won't really
happen in practice, but fix the leak nonetheless.

Fixes: e3a55b53 ("mac80211: validate cipher scheme PN length better")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/main.c

@@ -770,10 +770,12 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
 
 		for (r = 0; r < local->hw.n_cipher_schemes; r++) {
 			suites[w++] = cs[r].cipher;
-			if (WARN_ON(cs[r].pn_len > IEEE80211_MAX_PN_LEN))
+			if (WARN_ON(cs[r].pn_len > IEEE80211_MAX_PN_LEN)) {
+				kfree(suites);
 				return -EINVAL;
 			}
 		}
+	}
 
 	local->hw.wiphy->cipher_suites = suites;
 	local->hw.wiphy->n_cipher_suites = w;