mac80211: don't reinit rate control when mesh sta exists

This fixes some unintended resets of the rate control statistics
when minstrel_ht is used resulting in non-optimal throughput on mesh
links.

Tested-by: Emanuel Taube <emanuel.taube@gmail.com>
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index ca52dfd..4b274e9 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -391,7 +391,8 @@
 		sta->ch_width = chandef.width;
 	}
 
-	rate_control_rate_init(sta);
+	if (insert)
+		rate_control_rate_init(sta);
 	spin_unlock_bh(&sta->lock);
 
 	if (insert && sta_info_insert(sta))