mpeg12dec: Remove unused swap_uv member from Mpeg1Context

libavcodec/mpeg12dec.c

@@ -45,7 +45,6 @@ typedef struct Mpeg1Context {
     int repeat_field; /* true if we must repeat the field */
     AVPanScan pan_scan;              /**< some temporary storage for the panscan */
     int slice_count;
-    int swap_uv;//indicate VCR2
     int save_aspect_info;
     int save_width, save_height, save_progressive_seq;
     AVRational frame_rate_ext;       ///< MPEG-2 specific framerate modificator