omx: always ignore OMX_ErrorPortUnpopulated
omx: always ignore OMX_ErrorPortUnpopulated

It is safe to ignore it always. Tizonia notifies this error to pass
some khronos conformance tests. Problem is that gst-omx saves this
error in comp->last_error and then gst_omx_port_set_enabled early
error out which fails the pipeline.

https://bugzilla.gnome.org/show_bug.cgi?id=782800

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