drm/i915: s/obj->exec_list/obj->obj_exec_link in debugfs

To convert the execbuf code over to use vmas natively we need to
shuffle the exec_list a bit. This patch here just prepares things with
the debugfs code, which also uses the old exec_list list_head, newly
called obj_exec_link.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Split out from Ben's big patch.]
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 2e7d5f9..6532d97 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1312,6 +1312,8 @@
 	struct list_head global_list;
 
 	struct list_head ring_list;
+	/** Used in execbuf to temporarily hold a ref */
+	struct list_head obj_exec_link;
 	/** This object's place in the batchbuffer or on the eviction list */
 	struct list_head exec_list;