avcodec/av1dec: Move message of OBU info back to the beginning

So that can show OBU info even it doesn't have decomposed content. And
add OBU content status into the message.

Signed-off-by: Fei Wang <fei.w.wang@intel.com>

libavcodec/av1dec.c

@@ -1200,11 +1200,12 @@ static int av1_receive_frame_internal(AVCodecContext *avctx, AVFrame *frame)
         AV1RawOBU *obu = unit->content;
         const AV1RawOBUHeader *header;
 
+        av_log(avctx, AV_LOG_DEBUG, "OBU idx:%d, type:%d, content available:%d.\n", i, unit->type, !!obu);
+
         if (!obu)
             continue;
 
         header = &obu->header;
-        av_log(avctx, AV_LOG_DEBUG, "Obu idx:%d, obu type:%d.\n", i, unit->type);
 
         switch (unit->type) {
         case AV1_OBU_SEQUENCE_HEADER: