v4l2: clear DISCONT flag when recycling buffers into the buffer pool

The base class may have set the DISCONT flag on the first buffer pushed
out. We need to clear that when recycling buffers back into the buffer
pool, otherwise we constantly push out buffers with the discont flag
set, which might upset downstream elements, esp. for compressed
formats like mpeg-ts.

sys/v4l2/gstv4l2bufferpool.c

@@ -98,6 +98,7 @@ gst_v4l2_buffer_finalize (GstV4l2Buffer * buffer)
     GST_LOG_OBJECT (pool->v4l2elem, "reviving buffer %p, %d", buffer, index);
     gst_buffer_ref (GST_BUFFER (buffer));
     GST_BUFFER_SIZE (buffer) = 0;
+    GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DISCONT);
     pool->buffers[index] = buffer;
   }