avcodec/utils: Align YUV411 by as much as the other YUV variants

Fixes out of array accesses
Fixes: ffmpeg_mjpeg_crash2.avi

Found-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Tested-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/utils.c

@@ -374,7 +374,7 @@ void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
     case AV_PIX_FMT_YUVJ411P:
     case AV_PIX_FMT_UYYVYY411:
         w_align = 32;
-        h_align = 8;
+        h_align = 16 * 2;
         break;
     case AV_PIX_FMT_YUV410P:
         if (s->codec_id == AV_CODEC_ID_SVQ1) {