mac80211: QoS multicast frames have No Ack policy

Previously QoS multicast frames had the Normal Acknowledgment QoS
control bits set. This would cause broadcast frames to be discarded by
peers with which we have a BA session, since their sequence number would
fall outside the allowed range. Set No Ack QoS control bits on multicast
QoS frames and filter these in de-aggregation code.

Signed-off-by: Thomas Pedersen <thomas@cozybit.com>

v2: Use proper QoS Ack Policy ctl field mask (Christian)

v3: Clean up conditional (Johannes)
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index ffc073a..66cedf6 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -128,6 +128,7 @@
 #define IEEE80211_QOS_CTL_ACK_POLICY_NOACK	0x0020
 #define IEEE80211_QOS_CTL_ACK_POLICY_NO_EXPL	0x0040
 #define IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK	0x0060
+#define IEEE80211_QOS_CTL_ACK_POLICY_MASK	0x0060
 /* A-MSDU 802.11n */
 #define IEEE80211_QOS_CTL_A_MSDU_PRESENT	0x0080
 /* Mesh Control 802.11s */