fftools/ffmpeg: move the hw_device_free_all() call to ffmpeg_cleanup()

Frees devices on failure as well as success.

fftools/ffmpeg.c

@@ -551,6 +551,8 @@ static void ffmpeg_cleanup(int ret)
     av_freep(&vstats_filename);
     of_enc_stats_close();
 
+    hw_device_free_all();
+
     av_freep(&filter_nbthreads);
 
     av_freep(&input_files);
@@ -2973,8 +2975,6 @@ static int transcode(void)
         exit_program(1);
     }
 
-    hw_device_free_all();
-
     return 0;
 }