GCS_MAVLink: move try_send_message handling of VIBRATION up

Also, use singleton to get ins

libraries/GCS_MAVLink/GCS.h

@@ -173,7 +173,7 @@ public:
 #endif
     void send_autopilot_version() const;
     void send_local_position() const;
-    void send_vibration(const AP_InertialSensor &ins) const;
+    void send_vibration() const;
     void send_home(const Location &home) const;
     void send_ekf_origin(const Location &ekf_origin) const;
     void send_servo_output_raw(bool hil);

libraries/GCS_MAVLink/GCS_Common.cpp

@@ -1496,8 +1496,10 @@ void GCS_MAVLINK::send_local_position() const
 /*
   send VIBRATION message
  */
-void GCS_MAVLINK::send_vibration(const AP_InertialSensor &ins) const
+void GCS_MAVLINK::send_vibration() const
 {
+    const AP_InertialSensor &ins = AP::ins();
+
     Vector3f vibration = ins.get_vibration_levels();
 
     mavlink_msg_vibration_send(
@@ -2671,6 +2673,11 @@ bool GCS_MAVLINK::try_send_message(const enum ap_message id)
         send_ahrs();
         break;
 
+    case MSG_VIBRATION:
+        CHECK_PAYLOAD_SIZE(VIBRATION);
+        send_vibration();
+        break;
+
     default:
         // try_send_message must always at some stage return true for
         // a message, or we will attempt to infinitely retry the