We could probably hit this already with our current async fbdev init,
but it's much easier to hit this with the new deferred fbdev setup
that I'm working on polishing.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170706130023.28417-2-daniel.vetter@ffwll.ch