mac80211: Fix ieee80211_rx_reorder_ampdu: ignore QoS null packets

This patch fixes the check at the entrance to ieee80211_rx_reorder_ampdu.
This check has been broken by 'mac80211: rx.c use new helpers'.

Letting QoS NULL packet in ieee80211_rx_reorder_ampdu led to packet loss in
RX.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 244ee2d..ba332c9 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2041,8 +2041,8 @@
 
 	tid_agg_rx = sta->ampdu_mlme.tid_rx[tid];
 
-	/* null data frames are excluded */
-	if (unlikely(ieee80211_is_nullfunc(hdr->frame_control)))
+	/* qos null data frames are excluded */
+	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
 		goto end_reorder;
 
 	/* new un-ordered ampdu frame - process it */