omxvideodec: use new libgstgl API since libgstegl has been removed
omxvideodec: use new libgstgl API since libgstegl has been removed

There is no point to retrieve a ref/unref type
instead of an EGLDisplay directly. It's like for EGLImage.

https://bugzilla.gnome.org/show_bug.cgi?id=703343

CapOM/gst-omx,pliu6/gst-omx,GStreamer/gst-omx,ismelykh/gst-omx-deinterlace,pliu6/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,GStreamer/gst-omx,CapOM/gst-omx,leio/gst-omx,renesas-rcar/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,GStreamer/gst-omx,varunkumara/test-repo,renesas-rcar/gst-omx,CapOM/gst-omx,leio/gst-omx,surround-io/gst-omx,renesas-rcar/gst-omx,varunkumara/test-repo,ismelykh/gst-omx-deinterlace,surround-io/gst-omx,varunkumara/test-repo