clk: renesas: cpg-mssr: Add R8A7742 support

Add RZ/G1H (R8A7742) Clock Pulse Generator / Module Standby and Software
Reset support, using the CPG/MSSR driver core and the common R-Car Gen2
(and RZ/G) code.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Link: https://lore.kernel.org/r/1587998460-7804-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>