mac80211: sync dtim_count to TSF

On starting a mesh or AP BSS, the interface dtim_count
countdown should match that of the driver TSF.

Signed-off-by: Thomas Pedersen <twpedersen@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index b62cbe8..ebf80f3 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -474,6 +474,7 @@
 		}
 	}
 
+	ieee80211_recalc_dtim(local, sdata);
 	return buflen;
 }
 IEEE80211_IF_FILE_RW(tsf);