iwlwifi: mvm: use RS macro instead of duplicating the code

There is a macro for converting TX response rate to a
rate scale value, use it.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/tx.c

@@ -1594,8 +1594,7 @@ static void iwl_mvm_rx_tx_cmd_agg(struct iwl_mvm *mvm,
 		mvmsta->tid_data[tid].tx_time =
 			le16_to_cpu(tx_resp->wireless_media_time);
 		mvmsta->tid_data[tid].lq_color =
-			(tx_resp->tlc_info & TX_RES_RATE_TABLE_COLOR_MSK) >>
-			TX_RES_RATE_TABLE_COLOR_POS;
+			TX_RES_RATE_TABLE_COL_GET(tx_resp->tlc_info);
 	}
 
 	rcu_read_unlock();