drm/i915/debugfs: Report ring in error state

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 54e5b2f..3f87860 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -182,6 +182,7 @@
 		u32 tiling:2;
 		u32 dirty:1;
 		u32 purgeable:1;
+		u32 ring:4;
 	} *active_bo;
 	u32 active_bo_count;
 	struct intel_overlay_error_state *overlay;