serial: sh-sci: Add device tree support for r8a7795 Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>