vfb: factor out method to add a crtc

3 jobs for vfb-add_crtc in 4 minutes and 36 seconds (queued for 4 seconds)
latest
Status Job ID Name Coverage
  Docker Image
passed #437657
debian-testing

00:00:22

 
  Build And Test
passed #437658
autotools-build-and-test

00:04:13

passed #437659
meson-build-and-test

00:02:14