avcodec/mpeg4videodec: Mark static table as const

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpeg4videodec.c

@@ -1298,7 +1298,7 @@ static int mpeg4_decode_mb(MpegEncContext *s, int16_t block[6][64])
     Mpeg4DecContext *ctx = (Mpeg4DecContext *)s;
     int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
     int16_t *mot_val;
-    static int8_t quant_tab[4] = { -1, -2, 1, 2 };
+    static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
     const int xy = s->mb_x + s->mb_y * s->mb_stride;
 
     av_assert2(s->h263_pred);