drm/i915: Show WT caching in debugfs

Add the missing cache-level to the describe_obj() function for debug and
error reporting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7ccb0cd..08e96a8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -324,7 +324,7 @@
 		u32 dirty:1;
 		u32 purgeable:1;
 		s32 ring:4;
-		u32 cache_level:2;
+		u32 cache_level:3;
 	} **active_bo, **pinned_bo;
 	u32 *active_bo_count, *pinned_bo_count;
 	struct intel_overlay_error_state *overlay;