vaapipostproc: enable advanced deinterlacing with same format.
vaapipostproc: enable advanced deinterlacing with same format.

If only advanced deinterlacing is requested, i.e. deinterlacing is
the only active algorithm to apply with source and output surface
formats being the same, then make sure to enable VPP processing.

Otherwise, allow fallback to bob-deinterlacing with simple rendering
flags alteration.

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