avfilter/buffersink: Remove outdated comments

These lists have size fields since
e48ded85.
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/buffersink.c

@@ -43,18 +43,18 @@ typedef struct BufferSinkContext {
     unsigned warning_limit;
 
     /* only used for video */
-    enum AVPixelFormat *pixel_fmts;           ///< list of accepted pixel formats, must be terminated with -1
+    enum AVPixelFormat *pixel_fmts;     ///< list of accepted pixel formats
     int pixel_fmts_size;
 
     /* only used for audio */
-    enum AVSampleFormat *sample_fmts;       ///< list of accepted sample formats, terminated by AV_SAMPLE_FMT_NONE
+    enum AVSampleFormat *sample_fmts;   ///< list of accepted sample formats
     int sample_fmts_size;
-    int64_t *channel_layouts;               ///< list of accepted channel layouts, terminated by -1
+    int64_t *channel_layouts;           ///< list of accepted channel layouts
     int channel_layouts_size;
-    int *channel_counts;                    ///< list of accepted channel counts, terminated by -1
+    int *channel_counts;                ///< list of accepted channel counts
     int channel_counts_size;
     int all_channel_counts;
-    int *sample_rates;                      ///< list of accepted sample rates, terminated by -1
+    int *sample_rates;                  ///< list of accepted sample rates
     int sample_rates_size;
 
     AVFrame *peeked_frame;