drm/i915: Stop consulting plane->fb

We want to get rid of plane->fb on atomic drivers. Stop looking at it.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180322152313.6561-10-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_fbdev.c

@@ -640,7 +640,7 @@ static bool intel_fbdev_init_bios(struct drm_device *dev,
 		if (!crtc->state->active)
 			continue;
 
-		WARN(!crtc->primary->fb,
+		WARN(!crtc->primary->state->fb,
 		     "re-used BIOS config but lost an fb on crtc %d\n",
 		     crtc->base.id);
 	}