iwlagn: remove unused variable

Some code was removed, but a variable it used
and that is now unused stayed around, kill it.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NWey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

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

@@ -233,7 +233,6 @@ u8 iwl_prep_station(struct iwl_priv *priv, struct iwl_rxon_context *ctx,
 	struct iwl_station_entry *station;
 	int i;
 	u8 sta_id = IWL_INVALID_STATION;
-	u16 rate;
 
 	if (is_ap)
 		sta_id = ctx->ap_sta_id;