Rover: support disabling rudder arming

APMrover2/radio.cpp

@@ -47,6 +47,12 @@ void Rover::init_rc_out()
 */
 void Rover::rudder_arm_disarm_check()
 {
+    // check if arming/disarm using rudder is allowed
+    AP_Arming::ArmingRudder arming_rudder = arming.rudder_arming();
+    if (arming_rudder == AP_Arming::ARMING_RUDDER_DISABLED) {
+        return;
+    }
+
     // In Rover we need to check that its set to the throttle trim and within the DZ
     // if throttle is not within trim dz, then pilot cannot rudder arm/disarm
     if (!channel_throttle->in_trim_dz()) {
@@ -79,7 +85,7 @@ void Rover::rudder_arm_disarm_check()
             // not at full right rudder
             rudder_arm_timer = 0;
         }
-    } else if (!g2.motors.active()) {
+    } else if ((arming_rudder == AP_Arming::ARMING_RUDDER_ARMDISARM) && !g2.motors.active()) {
         // when armed and motor not active (not moving), full left rudder starts disarming counter
         if (channel_steer->get_control_in() < -4000) {
             const uint32_t now = millis();