mac80211: move mesh related station fields to own struct

There are now a fairly large number of mesh fields that really
aren't needed in any other modes; move those into their own
structure and allocate them separately.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index 085edc1..cd02810 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -862,7 +862,7 @@
 
 	rcu_read_lock();
 	sta = sta_info_get(sdata, mgmt->sa);
-	if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
+	if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 		rcu_read_unlock();
 		return;
 	}