drm: use drm_file to tag vm-bos

Rather than using "struct file*", use "struct drm_file*" as tag VM tag for
BOs. This will pave the way for "struct drm_file*" without any "struct
file*" back-pointer.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20160901124837.680-3-dh.herrmann@gmail.com
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 8ab9ce5..66f31c3 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1315,7 +1315,8 @@
 {
 	struct nouveau_bo *nvbo = nouveau_bo(bo);
 
-	return drm_vma_node_verify_access(&nvbo->gem.vma_node, filp);
+	return drm_vma_node_verify_access(&nvbo->gem.vma_node,
+					  filp->private_data);
 }
 
 static int