hackrfinput - add auto bandpass filter selection

Add button to auto select the bandpass filter based on the sample rate. It matches the automatic selection done by libhackrf when sample rate is changed.

plugins/samplesource/hackrfinput/hackrfinputsettings.cpp

@@ -39,6 +39,7 @@ void HackRFInputSettings::resetToDefaults()
 	m_vgaGain = 16;
 	m_dcBlock = false;
 	m_iqCorrection = false;
+	m_autoBBF = true;
 	m_devSampleRate = 2400000;
     m_transverterMode = false;
 	m_transverterDeltaFrequency = 0;
@@ -71,6 +72,7 @@ QByteArray HackRFInputSettings::serialize() const
     s.writeBool(18, m_transverterMode);
     s.writeS64(19, m_transverterDeltaFrequency);
     s.writeBool(20, m_iqOrder);
+    s.writeBool(21, m_autoBBF);
 
 	return s.final();
 }
@@ -117,6 +119,7 @@ bool HackRFInputSettings::deserialize(const QByteArray& data)
         d.readBool(18, &m_transverterMode, false);
         d.readS64(19, &m_transverterDeltaFrequency, 0);
         d.readBool(20, &m_iqOrder, true);
+        d.readBool(21, &m_autoBBF, true);
 
 		return true;
 	}