v4l2: create file @doxy from text in the copyright header

libavdevice/v4l2.c

 /*
- * Video4Linux2 grab interface
  * Copyright (c) 2000,2001 Fabrice Bellard
  * Copyright (c) 2006 Luca Abeni
  *
- * Part of this file is based on the V4L2 video capture example
- * (http://v4l2spec.bytesex.org/v4l2spec/capture.c)
- *
- * Thanks to Michael Niedermayer for providing the mapping between
- * V4L2_PIX_FMT_* and PIX_FMT_*
- *
- *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
@@ -27,6 +19,17 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/**
+ * @file
+ * Video4Linux2 grab interface
+ *
+ * Part of this file is based on the V4L2 video capture example
+ * (http://v4l2spec.bytesex.org/v4l2spec/capture.c)
+ *
+ * Thanks to Michael Niedermayer for providing the mapping between
+ * V4L2_PIX_FMT_* and PIX_FMT_*
+ */
+
 #undef __STRICT_ANSI__ //workaround due to broken kernel headers
 #include "config.h"
 #include <unistd.h>