GCS_MAVLink: remove unneeded telemetry_delayed parameter

Also make it protected

libraries/GCS_MAVLink/GCS.h

@@ -212,10 +212,6 @@ public:
     // return current packet overhead for a channel
     static uint8_t packet_overhead_chan(mavlink_channel_t chan);
 
-    // FIXME: move this to be private/protected once possible
-    bool telemetry_delayed(mavlink_channel_t chan);
-    virtual uint32_t telem_delay() const = 0;
-
 protected:
 
     // overridable method to check for packet acceptance. Allows for
@@ -269,6 +265,9 @@ protected:
     void handle_timesync(mavlink_message_t *msg);
     void handle_statustext(mavlink_message_t *msg);
 
+    bool telemetry_delayed() const;
+    virtual uint32_t telem_delay() const = 0;
+
 private:
 
     float       adjust_rate_for_stream_trigger(enum streams stream_num);

libraries/GCS_MAVLink/GCS_Common.cpp

@@ -1520,13 +1520,13 @@ float GCS_MAVLINK::adjust_rate_for_stream_trigger(enum streams stream_num)
 }
 
 // are we still delaying telemetry to try to avoid Xbee bricking?
-bool GCS_MAVLINK::telemetry_delayed(mavlink_channel_t _chan)
+bool GCS_MAVLINK::telemetry_delayed() const
 {
     uint32_t tnow = AP_HAL::millis() >> 10;
     if (tnow > telem_delay()) {
         return false;
     }
-    if (_chan == MAVLINK_COMM_0 && hal.gpio->usb_connected()) {
+    if (chan == MAVLINK_COMM_0 && hal.gpio->usb_connected()) {
         // this is USB telemetry, so won't be an Xbee
         return false;
     }