drm/i915: Use crtc->state in intel_fbdev_init_bios

fbdev init shouldn't race with userspace since it's called from
intel_modeset_init, so it's safe to dereference crtc->state and
assume nothing changed yet.

At least not more harmful than crtc->config.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181004094604.2646-11-maarten.lankhorst@linux.intel.com