drm/i915: Rename the gtt_list to global_list

Since it will be used for the global bound/unbound list with full PPGTT,
this helps clarify things for upcoming code rework.

Recommended-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-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 be869f2..3acf3f5 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1154,7 +1154,7 @@
 	struct drm_mm_node *gtt_space;
 	/** Stolen memory for this object, instead of being backed by shmem. */
 	struct drm_mm_node *stolen;
-	struct list_head gtt_list;
+	struct list_head global_list;
 
 	/** This object's place on the active/inactive lists */
 	struct list_head ring_list;