avcodec/mpegvideo: Move ASM-offset warning to its proper place

Reviewed-by: Peter Ross <pross@xvid.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/mpegvideo.h

@@ -77,13 +77,14 @@ typedef struct MpegEncContext {
 
     /* scantables */
     ScanTable inter_scantable; ///< if inter == intra then intra should be used to reduce the cache usage
-    ScanTable intra_scantable;
-    ScanTable intra_h_scantable;
-    ScanTable intra_v_scantable;
 
     /* WARNING: changes above this line require updates to hardcoded
      *          offsets used in ASM. */
 
+    ScanTable intra_scantable;
+    ScanTable intra_h_scantable;
+    ScanTable intra_v_scantable;
+
     struct AVCodecContext *avctx;
     /* The following pointer is intended for codecs sharing code
      * between decoder and encoder and in need of a common context to do so. */