drm/tegra: dc: Register debugfs in ->late_register()

The ->late_register() and ->early_unregister() callbacks are called at
the right time to make sure userspace only accesses interfaces when it
should. Move debugfs registration and unregistration to these callback
functions to avoid potential races with userspace.

Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dc.h

@@ -56,8 +56,6 @@ struct tegra_dc {
 	struct list_head list;
 
 	struct drm_info_list *debugfs_files;
-	struct drm_minor *minor;
-	struct dentry *debugfs;
 
 	/* page-flip handling */
 	struct drm_pending_vblank_event *event;