The SSSE3 version of dct_quantize in mpegvideo_mmx_template.c needs

inv_zigzag_direct16 16-byte aligned, so mark it appropriately.
Fixes encoder crashes e.g. with MPlayer's -vf lavc.

Originally committed as revision 21389 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dsputil.c

@@ -87,7 +87,7 @@ const uint8_t ff_zigzag248_direct[64] = {
 };
 
 /* not permutated inverse zigzag_direct + 1 for MMX quantizer */
-DECLARE_ALIGNED_8(uint16_t, inv_zigzag_direct16)[64];
+DECLARE_ALIGNED_16(uint16_t, inv_zigzag_direct16)[64];
 
 const uint8_t ff_alternate_horizontal_scan[64] = {
     0,  1,   2,  3,  8,  9, 16, 17,