The VA display attributes are mapped to properties so that to maintain the
GStreamer terminology. Properties are to be identified by name, but internal
functions are available to lookup the property by the actual VA display
attribute type.
Move display types from gstvaapipluginutil.* to gstvaapidisplay.* so that
we could simplify characterization of a GstVaapiDisplay. Also rename "auto"
type to "any", and add a "display-type" attribute.
several times. This fixes decoding of MPEG-2 and H.264
because those created a GstVaapiContext later through
avcodec_decode_video() that was a protected call.