rtl_tcp: update rtl agc mode as well when switching tuner agc on/off

lib/rtl_tcp/rtl_tcp_source_c.cc

@@ -318,6 +318,7 @@ osmosdr::gain_range_t rtl_tcp_source_c::get_gain_range( const std::string & name
 bool rtl_tcp_source_c::set_gain_mode( bool automatic, size_t chan )
 {
   _src->set_gain_mode(int(!automatic));
+  _src->set_agc_mode(automatic);
 
   _auto_gain = automatic;
 

lib/rtl_tcp/rtl_tcp_source_f.cc

@@ -308,3 +308,9 @@ void rtl_tcp_source_f::set_if_gain(int stage, int gain)
   struct command cmd = { 0x06, htonl(params) };
   send(d_socket, (const char*)&cmd, sizeof(cmd), 0);
 }
+
+void rtl_tcp_source_f::set_agc_mode(int on)
+{
+  struct command cmd = { 0x08, htonl(on) };
+  send(d_socket, (const char*)&cmd, sizeof(cmd), 0);
+}

lib/rtl_tcp/rtl_tcp_source_f.h

@@ -112,6 +112,7 @@ public:
   void set_gain(int gain);
   void set_freq_corr(int ppm);
   void set_if_gain(int stage, int gain);
+  void set_agc_mode(int on);
 };