weston: Remove weston@service and rely on the poky provided variant
Also adapt the imx6ull override and the sed command to set the fbdev backend for weston.
Dear all, On Thursday, 4th September 2025, we will test the new disaster recovery environment. A disaster recovery test will take place between 4:00 PM and 6:00 PM CEST. Please refrain from making any changes, as they will be lost. Once testing is complete, the production environment will be restored. Thank you for your understanding.
Also adapt the imx6ull override and the sed command to set the fbdev backend for weston.