cfg80211: use key size constants

Instead of hardcoding the key length for validation, use the
constants Zhu Yi recently added and add one for AES_CMAC too.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 34de8b2..a9173d5 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1092,6 +1092,7 @@
 	WLAN_KEY_LEN_WEP104 = 13,
 	WLAN_KEY_LEN_CCMP = 16,
 	WLAN_KEY_LEN_TKIP = 32,
+	WLAN_KEY_LEN_AES_CMAC = 16,
 };
 
 /*