ArduCopter motors_y6: rewrite loop in terms of motors

ArduCopter/motors_y6.pde

@@ -108,9 +108,8 @@ static void output_motors_armed()
 
 	// this filter slows the acceleration of motors vs the deceleration
 	// Idea by Denny Rowland to help with his Yaw issue
-	for(int8_t i = CH_1; i <= CH_8; i++ ) {
-    	if(i == CH_5 || i == CH_6)
-    		continue;
+	for(int8_t m = 0; m <= 6; m++ ) {
+    	int i = ch_of_mot(m);
 		if(motor_filtered[i] < motor_out[i]){
 			motor_filtered[i] = (motor_out[i] + motor_filtered[i]) / 2;
 		}else{