fix in case g_omx_port_set_video_formats() is called once in executing state
fix in case g_omx_port_set_video_formats() is called once in executing state

In cases of codec_data, if we actually do get an OMX_EventPortSettingsChanged event, then this could trigger g_omx_port_set_video_formats() to be called again once in executing state.  In this case, just pick the current fourcc value, and don't try to change format.

mrchapp/gst-openmax,mrchapp/gst-openmax,mrchapp/gst-openmax,mrchapp/gst-openmax-devel,mrchapp/gst-openmax-devel,mrchapp/gst-openmax-devel