FileSource: put center frequency and sample rate in the settings structure

plugins/samplesource/filesource/filesourcesettings.cpp

@@ -25,6 +25,8 @@ FileSourceSettings::FileSourceSettings()
 
 void FileSourceSettings::resetToDefaults()
 {
+    m_centerFrequency = 435000000;
+    m_sampleRate = 48000;
     m_fileName = "./test.sdriq";
 }
 

plugins/samplesource/filesource/filesourcesettings.h

@@ -21,6 +21,8 @@
 #include <QByteArray>
 
 struct FileSourceSettings {
+    quint64 m_centerFrequency;
+    qint32  m_sampleRate;
     QString m_fileName;
 
     FileSourceSettings();