iwlwifi: set correct single/dual stream mask

Even the initial single/dual stream values will be overridden later when
issue link quality command; but still make sense not to use hard-code
value during initialization. Single/Dual stream mask are used to indicate the
best antenna for SISO/MIMO; different NIC has different tx antenna
configuration; so the parameter need to based on the valid tx antenna.

1x2 device: single tx antenna available, only SISO is valid
configuration, but still need to set up MIMO configuration, so set it up
with antenna A & B as default.
2x2 device: two tx antenna available, dual_stream will use both valid
antenna.

3x3 device: three tx antenna available, skip the first antenna and
choice the second and third antenna for dual_stream.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index 3c1cd41..5bc406c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -2557,8 +2557,17 @@
 		     lq_sta->active_mimo3_rate);
 
 	/* These values will be overridden later */
-	lq_sta->lq.general_params.single_stream_ant_msk = ANT_A;
-	lq_sta->lq.general_params.dual_stream_ant_msk = ANT_AB;
+	lq_sta->lq.general_params.single_stream_ant_msk =
+		first_antenna(priv->hw_params.valid_tx_ant);
+	lq_sta->lq.general_params.dual_stream_ant_msk =
+		priv->hw_params.valid_tx_ant &
+		~first_antenna(priv->hw_params.valid_tx_ant);
+	if (!lq_sta->lq.general_params.dual_stream_ant_msk) {
+		lq_sta->lq.general_params.dual_stream_ant_msk = ANT_AB;
+	} else if (num_of_ant(priv->hw_params.valid_tx_ant) == 2) {
+		lq_sta->lq.general_params.dual_stream_ant_msk =
+			priv->hw_params.valid_tx_ant;
+	}
 
 	/* as default allow aggregation for all tids */
 	lq_sta->tx_agg_tid_en = IWL_AGG_ALL_TID;