Provide dummy cpg_mstp_{at,de}tach_dev() PM Domain callbacks if CPG/MSTP
support is not included, so the rcar-sysc driver won't have to care
about this.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>