Revert "avcodec/bsf: Forbid packet without payload in av_bsf_send_packet"

This reverts commit bfdca87a.

Packets with no data or side data will be valid EOF signal in an
upcoming merge.
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/avcodec.h

@@ -6039,8 +6039,7 @@ int av_bsf_init(AVBSFContext *ctx);
  * av_bsf_receive_packet() repeatedly until it returns AVERROR(EAGAIN) or
  * AVERROR_EOF.
  *
- * @param pkt the packet to filter. pkt must contain some payload (i.e data or
- * side data must be present in pkt). The bitstream filter will take ownership of
+ * @param pkt the packet to filter. The bitstream filter will take ownership of
  * the packet and reset the contents of pkt. pkt is not touched if an error occurs.
  * This parameter may be NULL, which signals the end of the stream (i.e. no more
  * packets will be sent). That will cause the filter to output any packets it

libavcodec/bsf.c

@@ -21,7 +21,6 @@
 #include "libavutil/log.h"
 #include "libavutil/mem.h"
 #include "libavutil/opt.h"
-#include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 
@@ -180,8 +179,6 @@ int av_bsf_send_packet(AVBSFContext *ctx, AVPacket *pkt)
         return 0;
     }
 
-    av_assert0(pkt->data || pkt->side_data);
-
     if (ctx->internal->eof) {
         av_log(ctx, AV_LOG_ERROR, "A non-NULL packet sent after an EOF.\n");
         return AVERROR(EINVAL);