CI: pipeline yocto: Change scope of CI_PARAM_IMAGE, ... to fix fngsystem build
The variables CI_PARAM_IMAGE, CI_PARAM_DISTRO, CI_MACHINE have been defined outside the job in the '.gitlab-ci.yml' file. This has a lower precedence then variables defined inside the job, but it seems that these variables are used in the scope of 'Trigger variables' when available in the trigger job. These override the value set in the template. As main results this made FNGSystem jobs build the normal yocto.