Add cubeb_stream_params::layout in the code example

include/cubeb/cubeb.h

@@ -53,12 +53,14 @@ extern "C" {
     output_params.format = CUBEB_SAMPLE_FLOAT32NE;
     output_params.rate = rate;
     output_params.channels = 2;
+    output_params.layout = CUBEB_LAYOUT_UNDEFINED;
     output_params.prefs = CUBEB_STREAM_PREF_NONE;
 
     cubeb_stream_params input_params;
     input_params.format = CUBEB_SAMPLE_FLOAT32NE;
     input_params.rate = rate;
     input_params.channels = 1;
+    input_params.layout = CUBEB_LAYOUT_UNDEFINED;
     input_params.prefs = CUBEB_STREAM_PREF_NONE;
 
     cubeb_stream * stm;