drm/i915: Capture interesting display registers on error

When trying to diagnose mysterious errors on resume, capture the
display register contents as well.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index bbcd5da..0b6052a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -766,6 +766,7 @@
 	do_gettimeofday(&error->time);
 
 	error->overlay = intel_overlay_capture_error_state(dev);
+	error->display = intel_display_capture_error_state(dev);
 
 	spin_lock_irqsave(&dev_priv->error_lock, flags);
 	if (dev_priv->first_error == NULL) {