Rover: GCS_MAVLink now uses Mission singleton

APMrover2/GCS_Mavlink.cpp

@@ -1222,11 +1222,6 @@ AP_VisualOdom *GCS_MAVLINK_Rover::get_visual_odom() const
 #endif
 }
 
-AP_Mission *GCS_MAVLINK_Rover::get_mission()
-{
-    return &rover.mission;
-}
-
 AP_Rally *GCS_MAVLINK_Rover::get_rally() const
 {
 #if AP_RALLY == ENABLED

APMrover2/GCS_Mavlink.h

@@ -14,7 +14,6 @@ protected:
     uint32_t telem_delay() const override;
     bool accept_packet(const mavlink_status_t &status, mavlink_message_t &msg) override;
 
-    AP_Mission *get_mission() override;
     AP_Rally *get_rally() const override;
     AP_AdvancedFailsafe *get_advanced_failsafe() const override;
     AP_VisualOdom *get_visual_odom() const override;