wireless: move mesh config length constant

This is a constant from the 802.11 specification.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 7372d7a..f5c7c33 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -159,7 +159,7 @@
 {
 	struct ieee80211_bss *bss;
 
-	if (mesh_config_len != MESH_CFG_LEN)
+	if (mesh_config_len != IEEE80211_MESH_CONFIG_LEN)
 		return NULL;
 
 	bss = kzalloc(sizeof(*bss), GFP_ATOMIC);