iwlwifi: beacon internal time unit

use TIME_UNIT define for beacon internal calculation
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -506,11 +506,11 @@ void iwl_setup_rxon_timing(struct iwl_priv *priv, struct ieee80211_vif *vif)
 	}
 
 	beacon_int = iwl_adjust_beacon_interval(beacon_int,
-				priv->hw_params.max_beacon_itrvl * 1024);
+				priv->hw_params.max_beacon_itrvl * TIME_UNIT);
 	priv->rxon_timing.beacon_interval = cpu_to_le16(beacon_int);
 
 	tsf = priv->timestamp; /* tsf is modifed by do_div: copy it */
-	interval_tm = beacon_int * 1024;
+	interval_tm = beacon_int * TIME_UNIT;
 	rem = do_div(tsf, interval_tm);
 	priv->rxon_timing.beacon_init_val = cpu_to_le32(interval_tm - rem);