decoder: h264: track corrupted frames.
decoder: h264: track corrupted frames.

Mark the picture as "corrupted" if it is reconstructed from corrupted
references or if those references are fake, e.g. resulting from lost
frames.

This is useful for notifying the upper layer, or downstream elements,
that the decoded frame may contain artefacts.

https://bugzilla.gnome.org/show_bug.cgi?id=703921

GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi,GStreamer/gstreamer-vaapi,CapOM/gstreamer-vaapi,ceyusa/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi