Refactoring: removed device parameter from all start() methods in sample source plugins

plugins/samplesource/hackrfinput/hackrfinput.cpp

@@ -99,7 +99,7 @@ bool HackRFInput::openDevice()
     return true;
 }
 
-bool HackRFInput::start(int device)
+bool HackRFInput::start()
 {
 //	QMutexLocker mutexLocker(&m_mutex);
     if (!m_dev) {

plugins/samplesource/hackrfinput/hackrfinput.h

@@ -71,7 +71,7 @@ public:
 	HackRFInput(DeviceSourceAPI *deviceAPI);
 	virtual ~HackRFInput();
 
-	virtual bool start(int device);
+	virtual bool start();
 	virtual void stop();
 
 	virtual const QString& getDeviceDescription() const;