drm/nouveau: remove as much direct use of core headers as possible

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_chan.c b/drivers/gpu/drm/nouveau/nouveau_chan.c
index 676b1b9..b63a56e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_chan.c
+++ b/drivers/gpu/drm/nouveau/nouveau_chan.c
@@ -22,10 +22,11 @@
  * Authors: Ben Skeggs
  */
 
-#include <core/object.h>
+#include <nvif/os.h>
+#include <nvif/class.h>
+
+/*XXX*/
 #include <core/client.h>
-#include <core/device.h>
-#include <core/class.h>
 
 #include "nouveau_drm.h"
 #include "nouveau_dma.h"