Rover: remove unneeded telemetry_delayed parameter

APMrover2/GCS_Mavlink.cpp

@@ -292,7 +292,7 @@ uint32_t GCS_MAVLINK_Rover::telem_delay() const
 // try to send a message, return false if it won't fit in the serial tx buffer
 bool GCS_MAVLINK_Rover::try_send_message(enum ap_message id)
 {
-    if (telemetry_delayed(chan)) {
+    if (telemetry_delayed()) {
         return false;
     }
 

APMrover2/Rover.h

@@ -450,7 +450,6 @@ private:
     void send_pid_tuning(mavlink_channel_t chan);
     void send_rangefinder(mavlink_channel_t chan);
     void send_current_waypoint(mavlink_channel_t chan);
-    bool telemetry_delayed(mavlink_channel_t chan);
     void gcs_data_stream_send(void);
     void gcs_update(void);
     void gcs_retry_deferred(void);