goom: Initialize the goom struct only once we know width/height and recreate it if those change
goom: Initialize the goom struct only once we know width/height and recreate it if those change

Fixes crash when the width and/or height is changing.

https://bugzilla.gnome.org/show_bug.cgi?id=762765

pexip/gst-plugins-good,hizukiayaka/gst-plugins-good,Kurento/gst-plugins-good,stfl/gst-plugins-good,pexip/gst-plugins-good,StreamUtils/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,Kurento/gst-plugins-good,hizukiayaka/gst-plugins-good,stfl/gst-plugins-good,StreamUtils/gst-plugins-good,stfl/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,Kurento/gst-plugins-good,hizukiayaka/gst-plugins-good,GrokImageCompression/gst-plugins-good,StreamUtils/gst-plugins-good,Kurento/gst-plugins-good,stfl/gst-plugins-good,hizukiayaka/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good,GStreamer/gst-plugins-good,GrokImageCompression/gst-plugins-good,GStreamer/gst-plugins-good,Kurento/gst-plugins-good,GStreamer/gst-plugins-good