proresenc: Don't free a buffer not owned by the codec

The data in coded_frame isn't allocated using get_buffer, but
is copied from the input frame to the encoder, so we should
not try to free it ourselves.

This fixes an assert failure when running in debug mode.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/proresenc.c

@@ -867,9 +867,6 @@ static av_cold int encode_close(AVCodecContext *avctx)
     ProresContext *ctx = avctx->priv_data;
     int i;
 
-    if (avctx->coded_frame->data[0])
-        avctx->release_buffer(avctx, avctx->coded_frame);
-
     av_freep(&avctx->coded_frame);
 
     if (ctx->tdata) {