soc: renesas: Add initial support for RA6M2 SoC

- Initial support for RA6M2 SoC

Signed-off-by: Tri Nguyen <tri.nguyen.wj@bp.renesas.com>
Signed-off-by: Danh Doan <danh.doan.ue@bp.renesas.com>
Signed-off-by: Duy Phuong Hoang. Nguyen <duy.nguyen.xa@renesas.com>