drm/todo: update the debugfs clean up task

The structs drm_debugfs_info and drm_debugfs_entry introduced a new
debugfs structure to DRM, centered on drm_device instead of drm_minor.
Therefore, remove the tasks related to create a new device-centered
debugfs structure and add a new task to replace the use of
drm_debugfs_create_files() for the use of drm_debugfs_add_file() and
drm_debugfs_add_files().

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219120621.15086-8-mcanal@igalia.com