ttm: Make parts of a struct ttm_bo_device global.

Common resources, like memory accounting and swap lists should be
global and not per device. Introduce a struct ttm_bo_global to
accomodate this, and register it with sysfs. Add a small sysfs interface
to return the number of active buffer objects.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/radeon/radeon_object.h b/drivers/gpu/drm/radeon/radeon_object.h
index 473e477..10e8af6 100644
--- a/drivers/gpu/drm/radeon/radeon_object.h
+++ b/drivers/gpu/drm/radeon/radeon_object.h
@@ -37,6 +37,7 @@
  * TTM.
  */
 struct radeon_mman {
+	struct ttm_bo_global_ref        bo_global_ref;
 	struct ttm_global_reference	mem_global_ref;
 	bool				mem_global_referenced;
 	struct ttm_bo_device		bdev;