omxvideodec: remove wrong SettingsChanged ack
omxvideodec: remove wrong SettingsChanged ack

Partially revert 1b7d0b8:
  omxvideodec: handle IL 1.2 behavior for OMX_SetParameter

It turned out it was a problem in the decoder which was
not updating some local variables upon SetParameter.

https://bugzilla.gnome.org/show_bug.cgi?id=783976

GStreamer/gst-omx,GStreamer/gst-omx,GStreamer/gst-omx