ArduPlane: rename and make enum RC_Channel::ControlType

Type:: is too generic; get_type should probably be get_control_type

ArduPlane/navigation.cpp

@@ -165,10 +165,10 @@ void Plane::calc_airspeed_errors()
             const float control_max = channel_throttle->get_range();
             const float control_in = get_throttle_input();
             switch (channel_throttle->get_type()) {
-                case RC_Channel::RC_CHANNEL_TYPE_ANGLE:
+            case RC_Channel::ControlType::ANGLE:
                     control_min = -control_max;
                     break;
-                case RC_Channel::RC_CHANNEL_TYPE_RANGE:
+            case RC_Channel::ControlType::RANGE:
                     control_mid = channel_throttle->get_control_mid();
                     break;
             }

ArduPlane/reverse_thrust.cpp

@@ -143,7 +143,8 @@ float Plane::get_throttle_input(bool no_deadzone) const
  */
 float Plane::get_adjusted_throttle_input(bool no_deadzone) const
 {
-    if ((plane.channel_throttle->get_type() != RC_Channel::RC_CHANNEL_TYPE_RANGE) || (g2.flight_options & FlightOptions::CENTER_THROTTLE_TRIM) == 0) { 
+    if ((plane.channel_throttle->get_type() != RC_Channel::ControlType::RANGE) ||
+        (g2.flight_options & FlightOptions::CENTER_THROTTLE_TRIM) == 0) {
        return  get_throttle_input(no_deadzone);
     }
     float ret = channel_throttle->get_range() * throttle_curve(aparm.throttle_cruise * 0.01, 0, 0.5 + 0.5*channel_throttle->norm_input());