HackRF input: continuous sample rate setting

plugins/samplesource/hackrfinput/hackrfinputgui.h

@@ -71,7 +71,6 @@ private:
 	int m_lastEngineState;
 
 	void displaySettings();
-	void displaySampleRates();
 	void displayBandwidths();
 	void sendSettings();
     void updateSampleRateAndFrequency();
@@ -79,6 +78,7 @@ private:
 private slots:
     void handleDSPMessages();
 	void on_centerFrequency_changed(quint64 value);
+	void on_newSampleRate_changed(quint64 value);
 	void on_LOppm_valueChanged(int value);
 	void on_dcOffset_toggled(bool checked);
 	void on_iqImbalance_toggled(bool checked);