avcodec/mpegvideo: remove empty comments

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

libavcodec/mpegvideo.h

@@ -172,7 +172,7 @@ typedef struct Picture{
     int mb_var_sum;             ///< sum of MB variance for current frame
     int mc_mb_var_sum;          ///< motion compensated MB variance for current frame
 
-    int b_frame_score;          /* */
+    int b_frame_score;
     int needs_realloc;          ///< Picture needs to be reallocated (eg due to a frame size change)
 
     int reference;