lavd/v4l2: Add ARGB and XRGB packed pixel formats

Formats ARGB32, XRGB32, ABGR32, and XBGR32 were added to V4L2 instead
of ill-defined deprecated RGB32/BGR32 pixel formats.

When pixel format is not specified explicitly FFmpeg tries formats in
order in which they are stored in the table. Therefore formats are
sorted as follows: BGR is preferred over RGB and XBGR is preferred
over ARGB, because it could give better performance by ignoring alpha
component.

libavdevice/v4l2-common.c

@@ -34,6 +34,12 @@ const struct fmt_map ff_fmt_conversion_table[] = {
     { AV_PIX_FMT_RGB565BE,AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB565X },
     { AV_PIX_FMT_BGR24,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR24   },
     { AV_PIX_FMT_RGB24,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB24   },
+#ifdef V4L2_PIX_FMT_XBGR32
+    { AV_PIX_FMT_BGR0,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_XBGR32  },
+    { AV_PIX_FMT_0RGB,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_XRGB32  },
+    { AV_PIX_FMT_BGRA,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_ABGR32  },
+    { AV_PIX_FMT_ARGB,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_ARGB32  },
+#endif
     { AV_PIX_FMT_BGR0,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR32   },
     { AV_PIX_FMT_0RGB,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB32   },
     { AV_PIX_FMT_GRAY8,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_GREY    },