Remove fixme that is based on the assumption of !direct_8x8_inference && MBAFF.

Originally committed as revision 15370 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264.c

@@ -2452,7 +2452,6 @@ static av_always_inline void hl_decode_mb_internal(H264Context *h, int simple){
                     fill_rectangle(ref, 4, 4, 8, (16+*ref)^(s->mb_y&1), 1);
                 }else{
                     for(i=0; i<16; i+=4){
-                        //FIXME can refs be smaller than 8x8 when !direct_8x8_inference ?
                         int ref = h->ref_cache[list][scan8[i]];
                         if(ref >= 0)
                             fill_rectangle(&h->ref_cache[list][scan8[i]], 2, 2, 8, (16+ref)^(s->mb_y&1), 1);