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: e3a55b5399d55 ("mac80211: validate cipher scheme PN length better")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 3c956c5..99d27ba 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -770,8 +770,10 @@
 
 		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;
+			}
 		}
 	}