dts: renesas: Fix ADC register size for Renesas RZ/G3S

Change the adc node's compatible of RZ/G3S to renesas,rz-adc-c
Fix ADC node register size for Renesas RZ/G3S

Signed-off-by: Phuc Pham <phuc.pham.xr@bp.renesas.com>
Signed-off-by: Tien Nguyen <tien.nguyen.zg@renesas.com>