vaapidecode: Expose the supported profiles as caps to upstream
vaapidecode: Expose the supported profiles as caps to upstream

This will allows the playbin to fallback to Software Decoder
if the Hardware Decoder does not support a particular profile.

https://bugzilla.gnome.org/show_bug.cgi?id=730997

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