Yocto ST-linux headless distribution

[SScar.2]

Hi there, 

I'm building an ST-Linux distribution with Yocto (ST Distribution package) on a custom board (based on STM32MP153), and, now that I've tested it, I need to optimize the final image.
My distribution should be completely headless (so no HMI and no library for graphics) and should be as small as possible.
I based my custom image on the st-image-core image, and, for example, I noticed that in the final distribution, there's a complete filesystem dedicated to ST demos, which at this stage is completely unuseful. 

Is there a way to remove that filesystem? Is there any common way to remove any graphics library (and maybe also the weston user!!)? 

Thanks a lot!