fftools/ffmpeg_opt: reduce indentation in map_auto_audio()

Fix indentation after the previous commit. Also use an early return to
save one extra indentation level.

fftools/ffmpeg_opt.c

@@ -2545,10 +2545,12 @@ static void map_auto_audio(OutputFile *of, AVFormatContext *oc,
                            OptionsContext *o)
 {
     InputStream *ist;
+    int best_score = 0, idx = -1;
 
         /* audio: most channels */
-        if (av_guess_codec(oc->oformat, NULL, oc->url, NULL, AVMEDIA_TYPE_AUDIO) != AV_CODEC_ID_NONE) {
-            int best_score = 0, idx = -1;
+    if (av_guess_codec(oc->oformat, NULL, oc->url, NULL, AVMEDIA_TYPE_AUDIO) == AV_CODEC_ID_NONE)
+        return;
+
     for (int j = 0; j < nb_input_files; j++) {
         InputFile *ifile = input_files[j];
         int file_best_score = 0, file_best_idx = -1;
@@ -2577,7 +2579,6 @@ static void map_auto_audio(OutputFile *of, AVFormatContext *oc,
     if (idx >= 0)
         new_audio_stream(o, oc, idx);
 }
-}
 
 static int open_output_file(OptionsContext *o, const char *filename)
 {