build: trivial fix
build: trivial fix

Let's make sure gstomx.conf is cleanly regenerated.

Signed-off-by: Felipe Contreras <de77a8b9cd239b204c19c52ed62e48ab47243362@nokia.com>

freedesktop-unofficial-mirror/gstreamer__attic__gst-openmax,matsu/gst-openmax,freedesktop-unofficial-mirror/gstreamer__attic__gst-openmax,matsu/gst-openmax