iwlwifi: do not set the sequence control bit is not needed

commit 123877b80ed62c3b897c53357b622574c023b642 upstream.

Check the IEEE80211_TX_CTL_ASSIGN_SEQ flag from mac80211, then decide how to
set the TX_CMD_FLG_SEQ_CTL_MSK bit. Setting the wrong bit in BAR frame whill
make the firmware to increment the sequence number which is incorrect and
cause unknown behavior.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 4974cd7..1ab1ef1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -385,7 +385,10 @@
 		tx_cmd->tid_tspec = qc[0] & 0xf;
 		tx_flags &= ~TX_CMD_FLG_SEQ_CTL_MSK;
 	} else {
-		tx_flags |= TX_CMD_FLG_SEQ_CTL_MSK;
+		if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ)
+			tx_flags |= TX_CMD_FLG_SEQ_CTL_MSK;
+		else
+			tx_flags &= ~TX_CMD_FLG_SEQ_CTL_MSK;
 	}
 
 	priv->cfg->ops->utils->tx_cmd_protection(priv, info, fc, &tx_flags);