Scanout bo placement issue

intel_user_framebuffer_create() has harsh requirements for scanout bos in discrete gpus.

It requires it to be placed only in lmem or be a dma-buf import. But this bring issues as Gallium/Iris create scanout buffers as export buffers as well and Iris places exported buffers in lmem and smem to allow access by other GPUs if needed.

So kmsbcube(https://gitlab.freedesktop.org/mesa/kmscube) can't create framebuffers and scanout to display.

Can't we relax requirements to create framebuffers to something like i915_gem_object_can_migrate()?