chroma: add avutil version check for YUV422P9LE/BE (fix #8249)

swscale is broken on systems with disable-avcodec (not meeting avcodec
version requirement).
According to ffmpeg commit e06be9eccdc969a9fd2736c2daf37c2fbccae37f
those chromas have been introduced after avutil 51.12.0.

modules/codec/avcodec/chroma.c

@@ -85,8 +85,10 @@ static const struct
     {VLC_CODEC_I420_9B, PIX_FMT_YUV420P9BE, 0, 0, 0 },
     {VLC_CODEC_I420_10L, PIX_FMT_YUV420P10LE, 0, 0, 0 },
     {VLC_CODEC_I420_10B, PIX_FMT_YUV420P10BE, 0, 0, 0 },
+#if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(51,13,0)
     {VLC_CODEC_I422_9L, PIX_FMT_YUV422P9LE, 0, 0, 0 },
     {VLC_CODEC_I422_9B, PIX_FMT_YUV422P9BE, 0, 0, 0 },
+#endif
     {VLC_CODEC_I422_10L, PIX_FMT_YUV422P10LE, 0, 0, 0 },
     {VLC_CODEC_I422_10B, PIX_FMT_YUV422P10BE, 0, 0, 0 },