drm/nvc0: import initial vm backend

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_mem.c b/drivers/gpu/drm/nouveau/nouveau_mem.c
index 2241811..07be1dd 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mem.c
@@ -731,6 +731,10 @@
 	if (ret)
 		return ret;
 
+	node->page_shift = 12;
+	if (nvbo->vma.node)
+		node->page_shift = nvbo->vma.node->type;
+
 	mem->mm_node = node;
 	mem->start   = node->offset >> PAGE_SHIFT;
 	return 0;