avfilter/buffersrc: add context to av_log() call

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

libavfilter/buffersrc.c

@@ -98,7 +98,7 @@ int attribute_align_arg av_buffersrc_add_frame_flags(AVFilterContext *ctx, AVFra
 
     if (frame && frame->channel_layout &&
         av_get_channel_layout_nb_channels(frame->channel_layout) != av_frame_get_channels(frame)) {
-        av_log(0, AV_LOG_ERROR, "Layout indicates a different number of channels than actually present\n");
+        av_log(ctx, AV_LOG_ERROR, "Layout indicates a different number of channels than actually present\n");
         return AVERROR(EINVAL);
     }