iwlwifi: add valid tx antenna information in rate_scale_table debugfs

when display rate_scale_table debugfs information, also display valid tx
antenna information, this will help user to select correct antenna when
issue fixed rate debugfs command

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Acked-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-rs.c

@@ -2526,7 +2526,9 @@ static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 	ssize_t ret;
 
 	struct iwl_lq_sta *lq_sta = file->private_data;
+	struct iwl_priv *priv;
 
+	priv = lq_sta->drv;
 	buff = kmalloc(1024, GFP_KERNEL);
 	if (!buff)
 		return -ENOMEM;
@@ -2537,6 +2539,10 @@ static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 			lq_sta->active_legacy_rate);
 	desc += sprintf(buff+desc, "fixed rate 0x%X\n",
 			lq_sta->dbg_fixed_rate);
+	desc += sprintf(buff+desc, "valid_tx_ant %s%s%s\n",
+	    (priv->hw_params.valid_tx_ant & ANT_A) ? "ANT_A," : "",
+	    (priv->hw_params.valid_tx_ant & ANT_B) ? "ANT_B," : "",
+	    (priv->hw_params.valid_tx_ant & ANT_C) ? "ANT_C" : "");
 	desc += sprintf(buff+desc, "general:"
 		"flags=0x%X mimo-d=%d s-ant0x%x d-ant=0x%x\n",
 		lq_sta->lq.general_params.flags,